In this paper, we review the research work in our group concerning the multi-component Fibonacci Sequence, Fibonacci metallic superlattices, as well as their structures, physical properties and applications.

Materials in thin film form are well known to have optical properties different from corresponding bulk materials. The refractive index of films is smaller; their structure may be columnar and this induces water absorption-desorption phenomena, anisotropy and instabilities when illuminated with a high power light flux.

Thickfilm technology has been used to prepare PbTiO₃ films. DC electrical conduction mechanism has been studied with the films and a diplacive second order phase transition is reported here. Compositional analysis and surface morphology of the films have been done by X-rays and S.E.M. Room temperature refractive index and permittivity studies in the millimeter wave lengths have been reported.

(Ga_1-x)In_xAs_1-ySb_y/InAs multilayers with cut off wavelength longer than 6 micrometers have been grown by Gd-doped step cooling liquid phase epitaxy (LPE) between 530 and 460 degree(s)C. The optical properties of epilayers were characterized by FTIR transmission measurement, photoluminescence (PL), Raman spectroscopy and spectro- ellipsometry. The results showed that InAsSb epilayers have high purity, and good homogenity. Photodetectors were fabricated using this material. A room temperature dark current near 1 mA at -0.5 V has been obtained.

This work aims at the investigation of chemical composition and interface structures of oxide prepared by pure water anodization using Auger electron spectroscopy (AES) and Infrared absorption spectroscopy (IRS) measurements. Results show that the growth of stoichiometric silicon dioxide film is possible with anodization as evidenced by the features of 1106 cm^-1 in infrared measurement. In addition, the IR absorbance and the peak locations decrease almost linearly as the oxide grows thicker. High contents of Si-H and Si-OH are found in anodic oxide. In AES study, we found that the slower the growth rate of the anodization, the stronger the Si-O bonds. This observation is ascribed to effect of stressing the oxide film in a high electric field for long duration. In annealing study, we found that the interface thickness and the binding energies of Si (LVV) and O (KLL), in the oxide film can be either increased or decreased, governed by the initial anodic oxides, by the thermal annealing. The oxygen atomic ratio in the bulk of the samples are in the range of 55 approximately equals 65%. After annealing, the oxygen atoms at the interface will migrate to the bulk of the oxide and the atomic ratio of oxygen increases to a value of about 70%.

EXAFS was used to investigate the structures of Mo/Si multilayers from 20 angstrom to 3000 angstrom period value. The results show the structural disorder of Mo atom neighbor environment was inreased while the thickness of Mo layer was thinner. For 20 angstrom and 50 angstrom period Mo/Si multilayers, the polycrystalline Mo layer vanish, the intended small period structure were destroyed by interdiffusion. The mixed layer is amorphous MoSi₂. EXAFS results confirm that there is a critical difficulty in fabricating small period Mo/Si multilayer with a high reflectivity.

A 3D atomistic thin film deposition model has been successfully developed. The effect of the atomic mobility on substrate and film surface has been studied by using the model that simulates 3D thin film images, surface profiles and cross-sectional area pictures. In addition, quantitative results of surface RMS roughness, average film thickness, atomic coordination number and its distribution, and solid fraction of the deposited thin films are obtained from the simulations. When the film surface mobility increases from 0.3 to 3.0, RMS roughness decreases from 6.5 to 1.1, solid fraction increases from 0.27 to 0.46 and average film thickness decreases from 40 to 28 due to the diminishing of the voids within the film. The FWHM of the atomic coordination distribution becomes narrower indicating the increased degree of crystallization. With the increase in surface mobility crossing the boundary 1.5, the film evolves from a porous or loose columnar structure with voids to a densely packed fibrous grain structure which can be categorized by the zone structure models.

By using the MBE technique, we fabricated a GaAs film which contains three Si (delta) -doping layers, which form a three QW structure. Transverse magnetoresistance, longitudinal magneto-resistance and Hall resistance have been measured at low temperature from 0.3 K to 4.2 K and high magnetic field up to 7 T. SdH oscillation of the transverse magnetoresistance and diamagnetic SdH oscillation of the longitudinal magnetoresistance have been observed. Based on the experimental results, mechanism of the longitudinal oscillation and the Hall oscillation have been discussed.

Ge nanocrystals embedded in a-SiN_x matrix were prepared by the PECVD method with SiH₄, GeH₄ and NH₃ mixed in H₂ plasma and followed the thermal-annealing treatment, which was based on the preferential chemical bonding formation of Si-N and Ge-Ge. The samples were characterized by infrared absorption, X-ray diffraction, Raman scattering spectra and TEM micrograph. Visible photoluminescence was observed at room temperature with the PL peak at about 560 nm and the linewidth about 0.45 eV. We are temporarily using the quantum confinement model to explain the PL mechanism.

Ge/Fe multilayers, which were prepared by electron beam evaporation, were annealed at temperatures between 200 and 450 degree(s)C, and the formations have been investigated. It was found that the structure of the surface layer and the interior is quite different. With the results of X-ray diffraction patterns and Mossbauer spectra, the different compound phases were found at different annealing temperature.

Formation characteristics and stability of TiN film as coating layer on (alpha) -Si film or as interlayer between W films or W and Si films have been studied by TEM, SAD and XRD. Experimental results show that sputtered nanometric TiN films are homogeneous polycrystalline with high stability: diffusion between TiN and W or TiN and Si can be neglected until 850 degree(s)C and there is no reaction of TiN with W or TiN with Si in these multilayers even if they are annealed up to 900 degree(s)C.

When annealed at various temperature the amorphous film of CoMnNiO deposited by R.F. Sputtering transforms into nano-crystalline and polycrystalline, and grain size increases with increasing annealing temperature and time. The study indicated that the resistivity of the nano-crystalline films is lot bigger than of the amorphous and ploycrystalline films, and the relations of material constant (B) to temperature (T) for the nano-films were peculiar. It was suspected that anomaly of the electrical properties relate to higher density of the grain boundary in the nano-film.

The study of lattice mismatch strain, composition mutation in Hg_1-xCd_xTe thin films, and intensive strain field which created from substrate and acrossed all epilayers was nondestructively carried out by X-ray double crystal diffraction and X-ray topography.

In the present paper the geometric structure of a recently found sort of Fullerene, Buckytubes, was described by considering them to be formed by rolling up graphite sheets in different manners. The empirical linear combination of atomic orbitals (LCAO) method was used to study their band structure, density of state (DOS) and optical properties. Our results show that their properties not only differ from graphite but also vary according to the diameter and the helicity of tubules. Under the tight-binding approximation scheme, the boundary condition is an important factor to determine the electronic properties of various Buckytubes. Finally, a rule for the electronic properties of Buckytubes was gained.

The microstructure of source material for depositing PbTe high refractive film has been investigated by transmission electron microscopy. The results indicate that the PbTe source material is in good monocrystalline form and the excess Te presents in the form of plate of 5-150 nm on {100} planes. Its density is about 10¹⁵ - 10¹⁶/cm³ and homogeneously distributed in the matrix.

Our recent work in seeking the confirmative experimental evidences which support the quantum confinement mechanism of visible light emission from porous silicon (PS) is presented. The first successful observation of efficient infrared up-conversion luminescence verifies that the PS sample is an assembly of quantum confined structures with reduced dimensionalities. A double-resonance enhanced third-order nonlinear optical process is suggested to interpret the experimental observation. The carrier transfer mechanism involved in the light emission process is studied by the picosecond time-resolved luminescence spectroscopy. A comprehensive luminescence model which takes account into both the effects of quantum confinement and of surface states as well as the carrier transfer dynamics is proposed.

We have successfully realized boron (delta) -function-shaped doping in the silicon epilayer by molecular beam epitaxy (MBE) with a B₂O₃ doping source. The sheet boron concentration N_(Beta ) of the boron (delta) doping layer can exceed 3.4 X 10¹⁴ cm^-2. The transmission electron microscopy (TEM) cross-section image shows the width of the (delta) doping layer is about 1.5 nm. Meanwhile, we have applied in situ Auger electron spectroscopy (AES) to quantitatively analyze the relationship of boron (delta) doping sheet concentration N_(Beta ) with the (delta) doping time. With the substrate temperature of 650 degree(s)C and the doping source temperature of 900 degree(s)C, for N_(Beta ) < 3.4 X 10¹⁴ cm^-2 (1/2 monolayer), boron incorporation onto Si (100) is proportional to the (delta) doping time, and the sticking coefficient is 4.4 X 10¹³ cm^-2/min; while for N_(Beta ) > 3.4 X 10¹⁴ cm^-2, the incorporation tends to saturate. The residual oxygen has not been detected even if N_(Beta ) is up to 4.4 X 10¹⁴ cm^-2.

In this work, a new theory is proposed to rectify the apparently inconsistent results reported by others. The new kinetics of constant current plasma anodization kinetics is developed based on the ionic transport of oxidizing species. Using the experimental observations that the oxide electric field can either remain unchanged or increase linearly with the oxide growth, both logarithm and power laws for oxide thickness growth are obtained. The theoretical model correlates very will with the experiments reported by others. Space charge built-up in the oxide film, which depends on the current density of the oxidizing species and the reaction rate, is proposed to be origin for oxide field variations and different growth laws of the anodization. At very high current densities (e.g. 10 mA/cm²), the oxygen ion density in the oxide film reaches its saturated value, the space charge distribution and then the oxide electric field remains unchanged and the oxide growth is governed by a logarithm law. When the supply of ions is greater than the ion consumption in reaction, the electric field increases and the oxide growth can be precisely described by a power law.

We report two kinds of method for preparing luminescent silicon films with quantum crystallites (QCs) structures: (1) Using laser annealing technique to crystallize ultrathin amorphous silicon layers which were constructed in a-Si:H/a-SiN_x:H multiquantum well (MQW) structures. (2) Applying the layer-by-layer deposition technique to the growth of silicon QCs by varying the hydrogen plasma exposure time. The novel structures of these two types of QCs films were characterized by X-ray diffraction and Raman scattering spectroscopy. The room temperature visible photoluminescence (PL) from Si QCs with size of 4 nm or less has been observed in most of samples.

We have applied the dual-beam photocurrent spectroscopy to study the excited defect states in a-Si:H. The pump beam is used to create the excited state while the second beam is used as a probe. It is shown that the anomalous band in dual-beam photocurrent spectra of a-Si:H results from a combination of two processes: photocurrent enhancement due to excitations by the probe light for the D⁰ states to the conduction band. Using the dual-beam photocurrent spectra, we measured the optical transition energy (0.77 eV) and the electron correlation energy (0.16 eV) for the filled D^- defects (i.e., excited D⁰ defects). The dual-beam photocurrent spectroscopy may also be used for study of deep gap states in other thin film semiconductors.

High quality SiO₂ layers were deposited on top of strained SiGe by direct photochemical vapor deposition with a deuterium lamp as the excitation source. It was found that the deposition rate increase linearly with the chamber pressure. Auger Electron spectroscopy profile shows that these is no Ge rejected and no Ge-rich layer formed after devices were fabricated. At room temperature, the leakage current is about 3 X 10^-9 A/cm² under a 2 X 10⁶ V/cm electric field. The breakdown field can reach over 16 MV/cm for these SiGe MOS diodes.

The anomalous damage behavior of BF₂⁺ implantation into silicon at 300 K and 77 K has been investigated by using grazing angle Rutherford backscattering and channeling in combined with transmission electron microscopy. The damage or the amorphous layer produced by BF₂⁺ implantation is different from other heavier ions (> ²⁷Al⁺). For BF₂⁺ implantation at 300 K, there are two damage peaks, one at a depth near the projectile range of the ions, the other at the near surface. While for BF₂⁺ implantation at 77 K, the damage or the amorphous layer first occurs at the surface, then the amorphous layer is extended to the bulk of silicon with increasing does.

Porous silicon was prepared by the anodization of p/p⁺ epitaxial c-Si wafer. Its structure was examined by electron microscopy, Raman spectrum and infrared spectrum. The results of examination show the porous Si consists of many nano-scale pores and crystalline slices, and at the surface of slices, there is a amorphous-like thin film containing Si-H, Si-O and Si-H₂ bonds. When the porous Si layer was excited with violetilight, bright visible photoluminescence can be observed. The origin of visible luminescence may be due to both the quantum confinement of carriers into the nano- scale slices (or pillars) and the fluorescence emission of the amorphous-like film containing Si-H, Si-O and Si-H₂ bonds.

The present paper reports on the sheet resistance of Semi-Insulating Oxygen-Doped Polysilicon (SIPOS) using ion implantation. The type of dopant implanted, implant dose and annealing temperature are influence the sheet resistance of implanted SIPOS film. In addition, the behaviors of oxygen and hydrogen in implanted SIPOS film have been described, so that may be form the conduction model. We used three samples with different oxygen content implanted by Boron (B), Phosphorus (P) and Arsenic (As) various ions and measured the sheet resistance of those samples. As it is well known, the electrical properties and microstructures of SIPOS films are very sensitive to the oxygen content, so we measure the changes of oxygen content and hydrogen content after implantation, and then the conduction of implanted SIPOS film have been analyzed in this paper.

The process of the porous silicon layer formation and etching off is a new generation surface micromachining technology. The key problem of using porous silicon as a sacrificial layer is to do research on the selectivity of porous layer formation. In this paper, we will present the experimental results about which that the silicon is transformed to porous silicon in concentrated HF solution, including the relationship with current density J (mA/cm²), HF concentration C (wt%) and the substrate resistivity ((Omega) cm). Besides, by using implantation and epitaxial methods to change the doping level of the mask, porous silicon can be locally formed, the thickness and the undercutting may be changed by the parameters described before.

The role of silicon hydride species in the photoluminescence intensity behavior of porous silicon (PS) has been studied. The surface coverage was monitored using Fourier Transform Spectroscopy (FTIR). Porous silicon sample sets was prepared by the anodization of p-type (111) Si (10 Ohm X cm) and of n-type (111) Si (0.01 Ohm X cm) under a various current density for a different time of anodization with light illumination and in the dark. We have observed non- monotonous dependencies of PL intensity, IR absorption at Si-H_n stretching and wagging modes as well as of p-type Si and n-type Si versus anodization time and current density. In particular, the levels of IR absorption at the different Si-H modes have no correlation themselves and only wagging mode (628 cm^-1) repeat the PL intensity behavior. To our opinion, the photoluminescence may originate from the specific combinations of the particle structure and sizes with the definite surface state conditions of the nanocrystalline porous silicon.

When the dicarbon point defect with photoluminescence line at 969 meV (7818 cm^-1) is thermally destroyed, previously unreported photoluminescence lines at 902.73 (7281), 919.72 (7418), 924.06 (7453), 935.09 (7542) and 949.85 meV (7661 cm^-1) are observed. It is shown that the point defects providing these photoluminescence lines consist of carbon and oxygen atoms. Previously reported photoluminescence sublines of the dicarbon center located at 951.16 (7671), 952.98 (7686), 953.96 (7694) and 956.91 meV (7718 cm^-1) are not observed in Czochralski silicon with high oxygen concentration. It is shown that vacancies are not the species to modify the dicarbon center forming these satellite sublines and interstitial silicon atoms are the remaining possibility.

By the use of total reflection of a laser beam to generate fluorescence in a second medium, surface contours of, e.g., cells may be determined with an accuracy of about 1-2 nm.

Based on the discussion of general principles and fundamental phenomena in nonlinear guided-wave optics, this article presents a review of second-order and third-order nonlinear optical waveguide devices including second harmonic generation, nonlinear directional coupler, nonlinear grating reflector, nonlinear M-Z interferomenter, etc.; the analysis and comparison of nonlinear waveguide materials and measurement techniques; and an review of the research fields and prospects of nonlinear integrated optics.

There are various kinds of thin film beamsplitters, such as flat or cubic types, and polarizing, nonpolarizing, partial polarizing, and dichroic beamsplitters, based on physical concepts, which have considerable influence on the quality of optical systems or instruments according to how these beamsplitters are designed and used. This paper presents the results of designing of high-polarizing beamsplitters in wide spectrum, dichroic polarizing beamsplitters, and infrared high polarizing beamsplitters with dichroic properties at visible spectrum, which are applied to scene projectors using liquid crystal light valves, color photolithography machines and so on.

We report a new type of binary-phase optical beam splitters combined with a two-dimensional Dammann grating and a Fresnel zone plate as one element which has both functions of beam splitting and focussing. Amorphous silicon nitride (a-SiN_x:H) thin films deposited by plasma enhanced chemical vapor deposition (PECVD) method have been used for fabricating such an optical element. We have obtained 3 X 3 arrays of equal intensity and focused beams which generated by the beam splitter based on our own design. The relative distribution error of the intensity in each beam of the array is less than 5%.

The Fe/Ag, Co/Cu multilayers made by r.f. sputtering were studied by the MOKE spectra. It is convinced that the conduction electrons of Ag in Fe/Ag and Cu in Co/Cu are spin polarized, but they show different behaviors.

The absorption coefficient is calculated using the density-density response function (chi) (q_(parallel),(omega) ;z,z'). The surface localized Tamm states yield an extra peak in the spectrum. The Coulomb interaction among the electrons shifts the resonant energy upward, changes the line shape, and leaves a weak but well-defined structure behind.

In this paper, normal incidence soft x-ray multilayer mirrors for 23.4 nm, 8.89 nm, and 4.47 nm have been fabricated by planar magnetron, the multilayer is characterized with low angle x-ray diffraction and TEM technique. The absolute reflectivity is measured at the synchronization radiation facility.

The fabrication and characterization of soft X-ray multilayer lamellar phase gratings are given simply in this paper. The measurement of optical performance of soft X-ray multilayer phase grating at Beijing Synchrotron Radiation Facility is described in detail. The measurement results are analyzed and also compared with the theory predication.

Pt/Co multilayered films were prepared by DC sputtering and electron beam evaporation and grazing angle X-ray reflectivity analysis was used to determine the film structure. It was found that the interfaces of the evaporated samples became flatter and more obscure when the substrate temperature rose. The sputtered samples had relatively flat interfaces and the atoms were more closely packed than the evaporated samples.

From the evaporating characteristic of source and some parameters of chamber, the authors of this paper derived out the equation of the contour of the mask which is used to coat linear variable filter (LVFs). According to the special length of substrate, we designed a mask which is used to coat LVFs of the spectra range of 8-14 micrometers by computer, and made stainless masks.

The rectangular variable wavelength filter (RVWF) is a new type filter which has the peak wavelength varied linearly with the rectangular substrate length direction. This paper present the principle of RVWF and the design of the films, and the coating technique. We also give the result of our experiment.

Blue potassium molybdenum bronze (BPMB) bulk material was usually prepared by electrolytic reduction of K₂M_oO₄-M_oO₃ melts. We propose a new method for preparing BPMB film by the simultaneous vacuum evaporation of potassium molybdate and molybdenum trioxide. The ratio of K/M_o in compound was obtained from the energy-dispersive spectrum. The transition and switching properties of mixed film with sandwich structure were measured. The results of the measurements reveal the metal-semiconductor transitions behavior in the temperature region of 165-180 K. The switching characteristic of the sandwich structure was achieved.

There are several standard design methods for common antireflection coatings at visible and infrared region, but it is not enough to give satisfactory design when such coatings are used at big incident angle. This paper presents how the statistical test method, combined with some physical concepts, is applied for designing the antireflection coating at incident angle of up to 66.7 degree at wide visible spectrum and for the single wavelength 1060 nm, which is significant for laser applications.

Recent progress in the understanding of the interface (surface) magnetocrystalline anisotropy is reviewed, including the spin-density functional calculation of iron and cobalt layers in the overlayer and sandwich structure formed with nonmagnetic Cu and Pd interfaces. General expression for the effective ligand interaction model is given, which gives elegant explanation to the first-principles results and in agreement with the experimental findings in the recent years.

The ZrO₂/Zircaloy-4 systems before and after Zr⁺ bombardment at low temperature have been studied by use of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It is shown that 100-keV Zr⁺ bombardment of ZrO₂/Zr-4 system at low temperature leads to significant changes of compositional distribution in depth, and meanwhile, results in the alteration of oxide film thickness. Such results may be governed by these factors, such as bombardment conditions, the thickness of ZrO₂ films before bombardment, the amount of surface chemisorption oxygen Oad bombarded into matrix due to collision, and the overlapping extent between oxide film and bombardment damage areas and so on. It is shown that Zr⁺ bombardment enhances oxygen diffusion towards matrix significantly, interface mixing is also observed. XPS is used to determine both compositional and valerice states changes.

Three kinds of SOI (Si on Insulator) samples, i.e., SIMOX (Separation by Implanted Oxygen), ZMR (Zone Melt Recrystallization) and DB (Direct Bond), have been optically characterized by measuring normal incidence reflectance R spectra from 200 to 2000 nm and spectroellipsometric parameters (Psi) and (Delta) from 230 to 700 nm. The sample structure analyzed is as follows; Air/SiO₂(d₀)/rough interface ((sigma) )/Si(d₁)/SiO₂(d₂)/Si. Using established values for n and k of Si and SiO₂, we performed fitting to get values of (sigma) , d₁ and d₂ with nm accuracy. It was found that (sigma) equals 0 for SIMOX while (sigma) equals 7.7 nm for ZMR. For DB initially (sigma) equals 0, but thinning treatment of top Si layer by intentional thermal oxidization followed by HF etching emerges surface roughness as large as (sigma) equals 3.3 nm. It was also found that the thickness of top SiO₂ layer d₀ is about 3.3 nm and affects mainly (Psi) and (Delta) while (sigma) affects mainly R spectra. It is shown that a method to calculate the influence of interface roughness using effective medium approximation (EMA), which is widely used in commercial ellipsometers, is not appropriate to explain experimental results.

This work studies the properties of oxide traps by measuring the temperature dependence of the current-voltage (IV) characteristics for temperature ranging from 100 to 423 K. Results show that the trapping behaviors of the nitrided oxides have different temperature dependencies from those of conventional thermal oxides. For nitrided oxide at low electric fields (approximately equals 6 MV/cm), the temperature dependencies of the IV curves for temperature less than 400 K shows an activation energy in the range of 0.117 approximately equals 0.168 eV. This effect is attributed to the shallow trap-assisted conduction. Poole-Frenkel or thermionic emission of trapped charges is significant for temperature greater than 400 K and the activation energy of the IV curves is about 0.143 eV. For nitrided oxide at high electric field and at low temperature lower than 130 K, shallow trap-assisted two- step tunnelling of electrons is very significant. In studying the temperature dependencies of the electronic trapping in nitrided oxides, we found that the density of trapped charges decreases as large as 36.7% for temperature rising from 100 to 423 K. It indicates that the shallow trap density in nitrided oxide is significantly larger than that of thermal oxides.

We report the effect of the well width on room temperature operation of II-VI p-i-n quantum Stark effect modulators using ZnSe-ZnCdSe multiple quantum well structures within ZnSe p-n junctions. Results are given for the theoretical calculation of exciton binding energy and Stark shift, absorption and differential absorption as a function of the applied electric field. An optimum well width is estimated in current structures for the achievement of the largest (Delta) T/T by means of both theoretical and experimental approaches.

Ti/Fe bilayers are deposited on SiO₂ substrate in ultra-high- vacuum environment (10^-9 Torr) in different sequence: SiO₂/Fe(200 angstrom)/Ti(300 angstrom) and SiO₂/Ti(300 angstrom)/Fe(200 angstrom). The interfaces of the films and their evolution at various annealing stages are studied by X-ray reflectivity measurements using high resolution triple-crystal X-ray diffractometer. The study shows that a different sequence of deposition results in different microstructure and affects subsequent evolution of the interfaces. It is also noticed that the annealed films are contaminated by the oxygen. Electron density profiles for the structures are obtained by nonlinear least square fits to the reflectivity curves.

A new type of roughness silver thin films deposited on fractal surfaces of (alpha) -Al₂O₃ ceramics were prepared by rf- magnetron sputtering. The electrical properties of the Ag films are strongly dependant on the air pressure around the sample. When air pressure decreases to a certain value, a big jump of electrical resistant happens and the Ag thin film exhibits nonlinear I-V behavior. When releasing air into the vacuum chamber and the air pressure is raised, the film resistance restores to the primitive value and the nonlinear behavior then disappears.

Valence-band offsets at lattice mismatched semiconductor heterojunctions are studied by using the interface-bond-polarity model with tight-binding approximation. The interface dipoles for lattice mismatched (001) III-V/IV heterojunctions are calculated based on the polarity of individual bond. It is found that the valence-band discontinuities depend strongly upon both of the strain conditions and the interface bond structures. An improved agreement of the calculated valence-band offsets with that of experimental measurement can be obtained by taking account of the strain effect and the interface dipole correction simultaneously.

Spontaneously ordered phases in random alloy semiconductor have been observed in Ga_0.5In_0.5P grown on GaAs substrate by organometallic vapor-phase epitaxy. Together with the GaInP alloy semiconductor, such spontaneous atomic ordering has been observed in other alloy semiconductors. Based upon the results by transmission electron diffraction measurements on these GaInP alloy semiconductors, the ordering in the atomic arrangement has been determined to the so- called CuPt-type structure which is equivalent to the [111]- oriented GaP-InP monolayer superlattice. We have systematically investigated the optical properties of these spontaneously ordered GaInP alloy semiconductors by using spectroscopic methods such as photoluminescence and electroreflectance. The results show anomalous behaviors in both the optical spectra, which are quite different from those observed in random GaInP alloy semiconductors.

The strain effects on GaInAs/AlInAs quantum wells grown on InP substrates were studied theoretically. Three structures, i.e., Ga_xIn_1-xAs/Al_0.48Ga_0.52As, Ga_0.47In_0.53As/Al_yIn_1-yAs and Ga_xIn_1-xAs/Al_yIn_1-yAs were analyzed. It was shown that the band alignments for the strained structures change obviously compared with the unstrained case. The type-I and type-II band lineups can be formed respectively for the heavy-hole and light-hole valence subbands. The strain effect on the band discontinuities give a possibility to control the band offset for Ga_xIn_1-xAs/Al_yIn_1-yAs quantum well structures by using the strained layers.

The influence of environmental parameters on the charge acceptance and dark decay rate of organic photoconductor for temperature from -10 degree(s)C to 80 degree(s)C and relative humidity from 25% to 95% has been studied. The decreasing charge acceptance and increasing dark decay rate of the photoconductor are due to the Poole-Frenkel-assisted bulk thermal emission of free holes from shallow and deep emission center with the energies of 0.66 eV and 0.95 eV above the valence band respectively. Above 90% RH, the xerographic characteristic deteriorates due to the decrease in resistivity involving contamination of impurity ions on the photoconductor thin film surface.

One organophosphrous compound, tertiarybutylphosphine has been investigated for their possible use as precursors in the metalorganic chemical vapor deposition (MOCVD). This material is less pyrophoric and less toxic than phosphine, the compound has used to grow epitaxial layers of InP on semi-insulating InP substrate using trimethylindium (TMIn) in a flowing hydrogen ambient. High quality InP epilayer have been successfully grown and specular surface was obtained at growth temperature 600 degree(s)C and x-ray was used to measure the lattice mismatch (Delta) a/a. The highest quality InP epilayer, which was grown at a V/III ratio of 60 and a growth pressure of 250 Torr, the highest n-type electron Hall mobility were 4500 cm²/Vs with the electron concentration of 3.4 X 10¹⁵ cm^-3 at 300 K and 18260 cm²/Vs with the electron concentration of 2.8 X 10¹⁵ cm^-3 at 77 K. The low temperature (10 K) photoluminescence optical properties measurements show intense near bandgap emission with a full width half maximum (FWHM) is about 8 meV.

Novel lattice-matched Fe:InP/InGaAs heterostructure MESFETs have been grown by metalorganic chemical vapor deposition (MOCVD). The resistivity of epitaxially grown Fe:InP layer typically exceeded 3 X 10⁸ (Omega) cm. High transconductance of 140 mS/mm is obtained for a 1-micrometers gate length MESFET fabricated by depositing the gate metallization directly on the semi-insulating Fe:InP layer. High-frequency S-parameter measurements of microwave characteristics indicated a projected maximum frequency of oscillation f_max equals 18 GHz but transducer gain cutoff occurred at approximately 7.3 GHz because of impedance mismatch and package parasitic. The planar semi- insulating Fe:InP layer enhances the Schottky barrier height and results in devices with excellent performances.

Various metals were evaporated on the n-GaSb epilayer grown by low pressure metal organic chemical vapor deposition (MOCVD) to form the Schottky contact. The barrier height is almost independent of the work function and is determined entirely by the doping and surface property of the semiconductor. These results are in good agreement with Bardeen model. The carrier transport of Pd/n-GaSb contacts was studied and analyzed to discuss the effect of doping level of GaSb epilayer on the barrier height of the contact.

Auger Electron spectrum (AES) study has been carried out on the anodic film which was deposited by electrochemical method on the surface of Hg_1-xCd_xTe (HCT) crystal with x approximately equals 0.21. The element depth profile within the film and at the interface with substrate crystal was analyzed by means of Ar⁺ ions sputtering. The influences of current density, potential and electrolyte concentration during electrochemical deposition on the film structure are manifested.

We have investigated the growth of beryllium thin films on (alpha) - Al₂O₃, Si (111), and Ge (111). In all cases, epitaxial Be films were obtained under the proper conditions. The effects of substrate temperature T on crystalline quality and surface structure were also studied. Samples were analyzed in situ using reflection high energy electron diffraction and ex situ with ion beam analysis, scanning electron microscopy, atomic force microscopy, and a variety of x-ray diffraction techniques. Studies showed an increase in crystalline quality with increased T, as well as the presence of a surface superstructure, probably (root)3 X (root)3, R30 degree(s), for films deposited on Si at T >= 300 degree(s)C and films on Ge at T >= 200 degree(s)C. To date, the highest quality Be films are those grown on Ge (111) at T equals 300 degree(s)C.

Amorphous semiconductors have been used as thin film transistor (TFT), solar cell, phototransistors. In this paper we study the charge collected properties of a-Si:H/a-Si_1-xC_x:H multilayer pin photodiode. In a-Si:H pin photodiode, the photogenerated carriers can be totally collected under strong electric field under reverse bias. However, our measurements show that in the a-Si:H/a-Si_1-xC_x:H multilayer pin photodiode photogenerated electrons and holes drift toward the electrodes under a certain bias, the total collected charge shows no saturation with bias and exhibits a continuous increas with reverse bias. We classify that the device works at two regions. In region I, the device behaves like a photodiode. This charge collection efficiency drop from theoretical value may indicate charge capture or confinement at the interfaces and trapping at the a-Si:H potential wells. These charges trapped or confined can be released at the interface and quantum well at higher electric field. In region II, above a critical bias voltage, the device works as a breakdown diode with a series photosensitive resistor which contributes higher collection efficiency, namely optical gain greater than unity.

Five Ge films with thickness 250, 20, 10, 5 and 1 nm were sputter deposited on fuzed quartz substrates and annealed at 700 degree(s)C for 1 hour in vacuum. Optical properties of those films were measured using a spectroellipsometer and spectrophotometers. The thickest film was used to determine annealing condition and it can be regarded as the bulk. Dielectric constants were analyzed by the use of model dielectric function developed by Adachi (Jpn. J. Appl. Phys. 32 (1993) 3168). Thickness dependence was clearly observed. The thinnest Ge film was alternately deposited with SiO₂ layer. Thickness of the SiO₂ layer was changed accordingly 1, 2 and 5 nm to change the volume fraction of Ge. Comparing extinction spectra between measured and calculated using multilayer model as well as effective medium approximation, we found that optical properties in very thin Ge layer is quite different from that of the bulk, suggesting appearance of the quantum size effects.

Evaporated tin sulphide thin films (SnS) have been prepared onto glass substrates maintained at fixed temperatures in the range 50-300 degree(s)C and controlled film thicknesses. The films are nonstoichiometric, containing both SnS and its higher derivative compounds with different compositions. X-ray results showed that SnS was initially formed at 100 degree(s)C, accumulating and eventually became a stable compound at a substrate temperature, T_s of 300 degree(s)C. Observation on SEM micrographs revealed the existence of nonoriented film structures at low T_s and compacted crystalline structures at T_s equals 300 degree(s)C with the associated change in grain sizes from 0.1 to 1.2 micrometers . Film conductivity increased from 0.62 to 2.54 Sm^-1 with increasing substrate temperature. The low temperature measurements showed that the films underwent hopping and free band conduction at temperatures lower and higher than 220 K, respectively. A further investigation on the film's transmittance spectrum shows the dependent of optical bandgaps (1.26-1.07 eV) with substrate temperatures; these were attributed to the changes in the film's compositions.

Al_xIn_1-xN thin films have been fabricated on (0001) oriented (alpha) --Al₂O₃ sapphire substrates by microwave- excited metalorganic vapor phase epitaxy. The properties of the films have been studied by the reflection high-energy electron diffraction technique, x-ray diffraction, and optical measurements. At growth temperature of 600 degree(s)C, single crystalline layers of Al_xIn_1-xN were obtained for the first time. The fundamental absorption edge of the Al_xIn_1-xN film varies continuously with composition.

The waveguiding epitaxial LiTaO₃ and LiNbO₃ films have been prepared on sapphire substrates by pulsed laser deposition technique. The as-grown films were characterized by Raman scattering, XRD and SEM techniques, which revealed that epitaxial LiTaO₃ and LiNbO₃ films with small roughness were achieved on (001) and (012) sapphire substrates, respectively. Optical waveguiding properties were demonstrated by m-line measurement of TM and TE modes.

Using highly hydrogen diluted silane as the reaction gas which was resolved with r.f. + d.c. double power sources, we have fabricated the nano-crystallite silicon (nc-Si) films. Based on the interfacial trap theory of poly-Si and revised by small size effect, we have got the relationship between conductivity of nc-Si films and defect levels in its interfacial region. Photoabsorption spectra and conductivity of nc-Si have been measured at low temperatures from 4.2 K to 77 K. According to theoretical analyses and experimental results, we suggest that the temperature behavior of the conductivity of nc-Si film is exponential at low temperature; the defect levels which are induced by interfaces are deep levels. Photoconduction experiments show that the carrier lifetime of nc-Si is as high as 10 ms, and the trap effects are very strong.

In this paper, for producing short wavelength laser, authors discuss a novel model of FEL--peroidic dielectric loaded FEL: and drive the quantitative relation between foil stack parameters and wiggler field parameters. This paper analysis also the approximate sinusoidal distribution character of the transverse wiggler field along the axis of solenoid.

InGaAs epitaxial layers (EL) have a number of physical properties which are very attracted for many practical applications. Special place in this system takes isoperiodical heterocomposition In_x Ga_1-xAs/InP, in order to receive EL's with minimum of mismatch on heterojunction. However lattice parameters of binary compounds InAs and GaAs which formed this solid solution differ by 7 percent. This is a reason of existence in In_x Ga_1-xAs considerable 'internal' strains, which are comparable with mixing enthalpy. Therefore phase transitions (ordering or clustering) take place in the solid solution. Such transitions decrease the system energy and may be occur during EL's growth. In this situation may be expected the fundamental properties dependence from thermal growth condition. In addition to the strains source inside EL's 'external' strains may be presented. They may be conditioned by EL's and substrate lattice mismatch, for example. Therefore it was interesting to retrace how physical properties of material change depending on layers lattice mismatch to substrate.

A brief review of the theoretical state of the art in the field of semiconductor interfaces is presented. It is shown that the important factor controlling the different semiconductor barrier heights is the density of states associated with the semiconductor dangling-bonds. passivated semiconductor surfaces present saturated dangling-bonds and have modified barrier heights. Results for hydrogen-passivated GaAs (110)-surfaces are presented; it is shown that the Schottky-barrier height formed by the deposition of a K-layer is sustantially changed by the hydrogen-passivation.

The physics and application of the intersubband transitions in GaAs/AlGaAs quantum well superlattice structures have been under intense investigation in recent years. In this report, theoretical design and experiment of three GaAs/AlGaAs quantum well superlattice samples are given in detail. The samples are grown by MBE technique on semi-insulating GaAs substrate. The three samples have different growth parameters and therefore different energy band structures. The transitions have bound to bound and bound to continuum states. Fourier Transform Infrared (FTIR) spectra and the infrared photoelectron tunneling (IPET) spectra are measured and the results agree well with each other and with the calculations.

In this paper a new, modified s-d model for studying the quantum well states in a metal space of a magnetic metal sandwich structure is presented. The model is based on the following consideration that (1) in the direction perpendicular to the surface the conduction electron is limited in an infinite deep potential well; (2) the localized magnetic moment model is adapted for describing the atoms in the ferromagnetic layers; (3) the spin-flip scattering process is neglected because of the Heisenburg interaction. The resulted electron states are that the energy level is split into two symmetrical ones for a ferromagnetic configuration, which is in agreement with the recent experiments on the exchange-split spin- polarized electronic states. It is found that this simple model can explain the oscillatory exchange coupling with long period well.

The photo-excited carrier distribution and radiative recombination efficiency in dryetched quantum well dots (QWDs) with diameters down to 80 nm have been investigated by photoluminescence (PL) spectroscopy and cathodoluminescence (CL) imaging. The quantum well dots were fabricated from lattice-matched single or multiple quantum well heterostructures with InGaAs well thicknesses ranging from 2 to 15 nm. Low temperature CL imaging indicated dot-to-dot variation of emission intensity. The PL efficiency exhibits no significant reduction for dot sizes larger than 170 nm. But for dot diameters smaller than approximately equals 100 nm, the PL intensity is not detectable. Such diminution of PL intensity is attributed to side wall damage due to reactive ion etching. For dot diameters smaller than 300 nm, PL peak energies shift to higher values, reaching a blue shift of approximately equals 3 meV for 128 nm diameter GSMBE grown dots and approximately equals 10 meV for 130 nm diameter MOCVD grown dots.

We reported deep-level-free band edge luminescence from strained SiGe/Si multiple quantum well structures grown by conventional solid source Si MBE. No-phonon (NP) transitions due to symmetry-breaking alloy disordering in SiGe layers and transverse optical (TO) phonon replicas were clearly identified. A high quality of crystallinity is essential to the efficient luminescence. The choice of a higher growth temperature, Ts equals 870 degree(s)C, beyond the conventional growth temperature window 400-600 degree(s)C, was found to be important for radioactive recombination in SiGe/Si QWs structures.

We introduce the bands mixing theory for energy state studies in heterostructures, and calculate the energy state in single quantum well structures by using this method. Complete Bloch functions are used to describe the energy states, a given state in a heterostructure is treated as a superposition of states or extended states of different energy bands. The numerical results and comparisons with the simple theory are presented.

ZnSe-based short period superlattice quantum well (SPSQW) with Te- doping have been fabricated by mean of atomic layer epitaxy. Luminescence from these SPSQW structures was strongly modified by spatially selective introduction of Te isoelectronic centers. Typical photoluminescence spectrum from well-'doped' SPSQW is a broad and very efficient emission band with large stokes shift due to radiative recombination of self-trapped excitons high-efficiently localized at the ZnSe-ZnTe interface. In some properly designed structures, recombination from free-quantum-well excitons can been observed due to the enhancement of quantum confinement. For barrier-doped SPSQW, free-quantum-well and self-trapped excitons can co-exist in a wide range of temperature due to the fact that they are separated from each other spatially. Room-temperature-luminescence was dominated by narrow recombination of quantum-well-excitons. The decay rate for the free excitons at the n equals 1 resonance from barrier-doped SPSQW has a long lifetime tail of more than 10 nsec. All the phenomena were discussed in term of doping position and doping density, using the model of exciton extrinsic self-trapping.

Two nondestructive methods, X-ray Fluorescence Spectrometry (XRE) and Electron Probe Micro Analyzer (EPMA) are studied for the composition analysis in thin film. The operation conditions and parameters of these two methods are discussed. An analysis precision with the standard deviation within 0.005 for the atomic ration of Pb/(Zr + Ti) was obtained by the XRF-FP method. The transformation of perovskite ferroelectric phase from an as-deposited amorphous film prepared by the multi target co-sputtering method with a post annealing process is investigated through the local area quantitative analysis by EPMA. The annealed film with the initial atomic ratio of Pb/(Zr + Ti) < 1.13 were found to be consisted of two phases, perovskite and pyrochlore phases, with the different composition for each other. The surplus of Pb in the initial composition was found to be desirable for getting the perovskite phase through the annealing process.

A first attempt to growth thin films of Nb doped PZT with 96% of Zr by pulsed laser deposition (PLD) has been done on Pt-sputtered Si (100) single crystal substrates. The target [1.5% Nb doped Pb(Zr_0.965Ti_0.035)O₃] has been ablated in oxygen atmosphere with a focused KrF excimer laser beam. By changing the laser repetition rate and the deposition time, the thickness of the films was selected in the 150-400 nm range. The lead deficiency of the film was reduced by using an oxygen pressure of 75 mTorr as well as by holding the substrates at temperatures not higher than 500 degree(s)C. The results of the characterization show that a first (150-180 nm) layer is the main responsible of the lead deficiency, the low resistivity and the lack of ferroelectric response of the films grown.

A new PZT/a-Si:H composite thin film is introduced in this paper. Its whole structure is pt/PZT/CR/a-Si:H/ITO. PZT thin film was prepared by RF sputtering method in the thickness of 0.5-1.0 micrometers , while a- Si:H thin film was prepared by RF glow discharge method with its thickness controlled to match the PZT thin film in resistance. The resistivity of a-Si:H thin film will drop about four order under optical exposure. Hence, when the composite thin film is exposed to light, the voltage applied to it will be transferred from a-Si:H to PZT. This composite thin film has many advantages such as fast response, high density, cheap price and easy match with Si integrated circuit. A lot of new devices can be designed with this thin film: Photoelectric switch, photomemory, optical sensor, etc.

Switching characteristics of ferroelectric thin films (10³ to 10⁴ angstrom) at the crossover field from subsonic (via domain wall motion) to supersonic (via random reversal of individual dipoles) switching is investigated. The switching behavior of TGS (singlecrystal) and PZT (ceramic) films is discussed.

This paper has studied the interface trap distributions and characteristics of novel thin rapid thermal nitrided SiO_xN_y film (RTNF) used for VLSI by the technique of avalanche hot-electron injection and the measurements of high frequency C-V and quasistatic C-V characteristics. The research results gave that the distribution relationship of midgap interface trap density of the thin RTNF with nitridation time presented 'turnaround effect'. The different kinds of electronic traps, existing in the RTNF and having disparity densities, have been observed. Results indicated that two kinds of fast interface traps, which have different properties, were generated in the Si/SiO_xN_y interface during avalanche hot-electron injection. The distribution on the density of two interface traps with forbidden band position is provided. A weakly 'N' type distribution relationship of the midgap interface trap density with the avalanche injection dose is also given. The theoretical analyses and discussions of these results are also made in this paper.

¹H NMR spectra were obtained for the Plasma-Enhanced Tetraethylorthosilicate (PETEOS) SiO₂ film. The ¹H spectra consisted of two components with different linewidths, being separated into a narrow Lorentzian and a broad Gaussian. The linewidths narrowed with increasing temperature.

[111]-oriented PLT films have been successfully grown onto platinum film substrates by the rf-magnetron sputtering method using Pb enriched PLT (85/15) powder targets. The sputtering conditions for growing [111]-oriented films were investigated. Crystallographic identifications of the films were made by the X-ray measurements. Dielectric, ferroelectric and pyroelectric properties of these films were measured. The dielectric constant of the highly [111]-oriented PLT film showed an anomaly at the transition point of around 300 degree(s)C and its value at room temperature was large as 1070, indicating that the PLT thin film with La rich composition is also available for the DRAM because of its large dielectric constant. The D-E hysteresis loops measurement has been carried out using the Sawyer-Tower circuit at 60 Hz. The asymmetric hysteresis loops were observed. The Pr and Ec were 8.5 (mu) C/cm² and 78 kV/cm, respectively. The pyroelectric coefficient of this film was determined as 30nC/cm²K even without a poling treatment. [111]-oriented PLT films sputtered on Pt/Ti/silicon substrates possess desirable properties for potential applications to pyroelectric and memory devices.

The properties of thin films may be enhanced greatly when the depositing atoms are subjected to low energy ion bombardment. The arc evaporation process offers the possibility of intrinsic self bombardment due to the high percentage of low energy ionized material present in the evaporant. The main restriction of microdroplets of cathode material also present in arc evaporation may be overcome by means of magnetic filtering enabling the deposition of high quality carbon, carbon nitride and TiN films. Furthermore, when the depositing metal ions are bombarded with energetic gaseous ions, the mechanical properties and stoichiometry of the films may be controlled further. The technique of Ion Assisted Arc Deposition (IAAD) permits the synthesis of hard materials including TiN onto ambient temperature substrates.

The nitrogen-rich silicon oxynitride thin film for gate insulator application has been studied in this work. The Plasma Enhanced Chemical Vapour Deposition (PECVD) process was carried out at 350 degree(s)C with a low power density (0.011 W/cm²). The Auger Electron Spectroscopy (AES) depth profiling and infrared absorption spectra show the film is composed of nitrogen-rich silicon oxynitride. MOS C-V measurements demonstrated that a pre-deposition plasma nitridation may result in a higher dielectric breakdown. The post- deposition densification can be used to remove the plasma induced damages, and the post-metallization annealing is effective in reducing the irradiation damage and obtaining a low interface state density.

The interfacial reaction of bilayer Co/Ti with epitaxially grown Si_1-xGe_x layer with x equals 0.2 was investigated in this work. The multilayer films were characterized by Rutherford Backscattering Spectroscopy (RBS), Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The experimental results show the formation of a multi-layer of TiN(O)/CoSi₂(Ge)/Si. A highly preferential orientation was observed for the formed CoSi₂(Ge) layer. The resulted resistivity of Co/Ti/SiGe/Si after a high temperature annealing is close to that of typical CoSi₂ film.

Effects of O₃ on the growth and electrical properties of Pb(Zr,Ti)O₃ (PZT) thin films grown by photoenhanced metalorganic chemical vapor deposition (MOCVD) were investigated. Ferroelectric PZT films were obtained by both MOCVD and photoenhanced MOCVD using (₃ at substrate temperatures higher than 560 degree(s)C. The crystalline orientation, growth rate and growth temperature were scarcely influenced by the use of O₃ and photoirradiation. However, in the leakage current characteristics, an improvement in breakdown voltage by the use of O₃ and photoirradiation was observed. From SEM observations, it was found that this improvement may be caused by the microscopic change in film structure.

Compound semiconductors are at the heart of todays advanced digital and optoelectronic devices. As device production levels increase, so too does the need for high throughput deposition systems. The vertical rotating disk reactor (RDR) has been scaled to dimensions allowing metal organic chemical vapor deposition (MOCVD) on multiple substrates located on a 300 mm diameter platter. This symmetric large area reactor affords easy access over a wide range of angles for optical monitoring and control of the growth process. The RDR can be numerically modeled in a straightforward manner, and we have derived scaling rules allowing the prediction of optimum process conditions for larger reactor sizes. The material results give excellent agreement with the modeling, demonstrating GaAs/AlAs structures with < +/- 0.9% thickness uniformities on up to 17-50 mm or 4-100 mm GaAs substrates. Process issues related to reactor scaling are reviewed. With high reactant efficiencies and short cycle times between growths, through the use of a vacuum loadlock, the costs per wafer are found to be dramatically less than in alternative process reactors. The high reactant utilization, in combination with a dedicated and highly efficient exhaust scrubbing system, minimizes the systems environmental impact.

HF acid eroded Si wafers were used as substrates for deposition diamond film by HFCVD. The nucleation process and film characteristics were studied. Enhanced nucleation density to the level for abraded Se substrate and pronounced (111) texture of the obtained continuous diamond film were observed.

CoSi₂ is being investigated intensively for microelectronics application recently. In this paper a new method of growing an epitaxial CoSi₂ film by solid state reaction of Co/Ti/Si and TiN/Co/Ti/Si multilayer is described. The variation of structure and sheet resistance of the film with thermal annealing temperature and time has bee investigated. The kinetics and mechanism of the CoSi₂ solid-state epitaxy are discussed.

The thermal oxidation kinetics of FeCrAl alloy thin films in ambient air been investigated in the temperature range 400 approximately equals 530 degree(s)C. The films were deposited on to oxidized single crystal silicon wafers and glass substrates with thermal evaporation. In the studied region the growth of oxides has been found to obey a parabolic growth-rate law, the oxidation mechanism has been analyzed with Wagner model. The rate constant k, is temperature dependent and satisfies the Arrhenius relationship. The activation enthalpy H_p is evaluated. Auger electron spectrometry and X-ray diffraction have been used to investigate depth distribution and valence state of metals and oxygen during oxide growth.

This paper reports a wet etching technique for the pattern of high-Tc superconducting thin film. The solutions of 3% H₃PO₄, saturated EDTA and saturated NH₄CL are used as the etchants. The samples of YBCO high-Tc superconducting thin film are etched with the etching solutions. The measure results show that the influence of the etching solutions on Tc is related to the bridge width. The measure results for 50 micrometers , 5 micrometers , and 2 micrometers bridge widths are given and the X-T and R-T curves of the samples are provided in this paper.

The thickness and Al content dependence of the electrical properties and the IR absorption due to free electron, of ZnO:Al films prepared by rf magnetron sputtering was studied. As a result, it was found that the increase in the carrier concentration and the Hall mobility with increasing film thickness was ascribed to the decrement of real surface, namely the decrease in the number of chemisorbed oxygen on surface, and the spectral absorption due to the free carrier was approximately proportional to (lambda) ³.

High temperature superconducting thin films of GdBa₂Cu₃O₇ (GBCO) were fabricated by de-magnetron sputtering on SrTiO₃, Zr(Y)O₂ (YSZ), MgO and LaAlO₃ (LAO) single crystal substrates. The X-ray diffraction and TEM analysis showed the films were grown epitaxially with the c-axis perpendicular to the substrates surface. The rocking curves of the film were as narrow as 0.4 degree(s) (FWHM). The zero resistance critical temperature of GBCO could be as high as 92 K, and the critical current density at 77 K and zero field were higher than 3 MA/cm². The reproducibility is very good. Microwave filters were prepared using the GBCO films on LAO. The maximum insert loss of the low pass filers with upper frequency of 7 GHz at 78 K and the band pass filters with the central frequency of 8.9 GHz and band width of 500 MHz at 77 K were 0.76 dB and 1.9 dB, respectively. The properties of infrared bolometers prepared using GBCO films on YSZ with NEP (noise equivalence power) of 1.2 X 10^-11 WHz^-1/2, detectivity D^* of 4.5 X 10⁹ cmHz^1/2/W and responsivity R_v of 1600 V/W have not changed noticeably in the period of half a year with more than 40 warm-cold cycles.

This paper reports a wet etching technique for the pattern of high-Tc superconducting thin film. The solutions of 3% H₃PO₄, saturated EDTA and saturated NH₄CL are used as the etchants. The samples of YBCO high-Tc superconducting thin film are etched with the etching solutions. The measure results show that the influence of the etching solutions on Tc is related to the bridge width. The measure results for 50 micrometers , 5 micrometers , and 2 micrometers bridge widths are given and the X-T and R-T curves of the samples are provided in this paper.

We have studied the rate of oxygen diffusion through ytterbium oxide (Yb₂O$3), a buffer and dielectric layer used in high critical temperature superconducting (HTSC) structures. An epitaxial bilayer film of Yb₂O₃ on YBa₂Cu$3)O_7-(delta ) (YBCO) was deposited onto an (001) oriented single crystal MgO substrate using the pulsed laser deposition technique. The rate of oxygen diffusion through the bilayer was investigated from 365 to 655 degree(s)C by post deposition annealing individual section of the bilayer in 0.5 atm of ¹⁸O enriched molecular oxygen gas. Secondary ion mass spectroscopy was used to depth profile ¹⁸O and ¹⁶O in each sample. Oxygen diffusion coefficients for Yb₂O₃ at 365, 465, 555 and 655 degree(s)C were determined to be roughly (6, 16, 360, and 200) X 10^-1, respectively. For temperatures greater than about 500 degree(s)C, these diffusion rates can limit oxygen intake into underlying YBCO films; therefore, HTSC multilayer devices that utilize Yb₂O₃ as a dielectric layer may require longer annealing cycles in order to fully oxygenate each underlying HTSC layer.

Superconducting Tl-Ba-Ca-Cu-O thin films have been fabricated by laser ablation. There are two steps in this process. First, an excimer laser is focused onto the Ba-Ca-Cu-O target forming a Ba-Ca-Cu-O plume. These particles are then deposited on substrate; second, the precursor films are placed into quartz tube to anneal in the presence of unfired Tl₂Ba₂Ca₂Cu₃O₁₀ pellet to form the superconducting phase. Zero-resistance temperature Tc and critical current density Jc of the best film were 12 Ik and 1 X 10⁶A/cm² (at 77 K) respectively. X-ray diffraction (XRD) and secondary electron microscope (SEM) have been used to study the crystalline structure, while the composition are analyzed by high energy ion backscattering and checked with energy dispersion X-ray analysis (EDAX) and secondary ion mass spectroscopy (SIMS). Results show that these superconducting films are predominately composed of the (2223) phase and highly oriented. A platelet structure plays an important role on the quality of film.

The constituents of the YBCO thin films deposited by DC magnetron sputtering will deviate from that of the target. The origin of that deviation was discussed and a method to monitor the film constituent was raised by measuring the intensity of each individual persistent line of yttrium, barium and copper from the discharge region.

Epitaxial YBa₂(Cu_1-xZn_x)₃O_7-(delta ) thin films were prepared by an inverted cylindrical magnetron sputtering technique. X-ray diffraction shows an epitaxial growth with the c axis perpendicular to the substrate surface. The surface morphology of the films was studied by scanning electron microscopy. Auger electron microscopy analysis reveals that there is a good homogeneity throughout the film thickness. The transport properties such as the resistivity and the Hall effect were studied. The critical current densities were obtained indirectly from the imaginary part of the complex AC- susceptibility, and directly from the transport measurement performed on film microbridges. Both indirect and direct measurements gave comparable results. The critical current densities are 1.6 X 10⁷ A/cm² and 8 X 10⁶ A/cm² at 77 K for the pure films deposited on SrTiO₃ and MgO substrates, respectively. The epitaxy and the values of T_c and J_c of the Zn-doped films are decreased with respect to those of the undoped films. It is found that the thermally activated flux creep model gives the best agreement with the J_c values of the pure and Zn-doped films, with a decrease of the activation energy U_O for the Zn-doped films.

This paper reports optical and electrical performance study of high Tc superconductors, especially YBaCuO film. The behavior of high Tc superconductors at or near Tc was studied in detail. A high Tc superconducting transition-edge bolometer has been fabricated from YBaCuO thin film on a (100) SrTiO₃ substrate. The performance of the bolometer was studied. By using of the detectors, we also studied the photoresponse of YBaCuO film to He-Ne laser and far infrared laser. At or near the middle point of the film's transition temperature, the obtained voltage response signal of YBaCuO film to 1.5 mW He-Ne laser chopped at a frequency of 0.1 Hz is 10 mV. The relationship between the photoresponce signal to material, temperature and chopping frequency was studied in detail.

In this paper the physical basis of advanced thin films for optical storage has been presented. The main attention has been paid on rare- earth transition metal alloy films for magneto-optical (M-O) storage and semiconductor alloy films for phase change (P-C) optical storage.

Significant enhancement of Fe atom magnetic moment was observed in Fe/nobel metal (Cu, Ag and Au) multilayers prepared by vapor-deposition, and a negative linear relationship was found between the maximum magnetic moment per Fe atom versus the difference of the covalent radius of the constituent metals. It was also found that Pd atoms in Pd/3d- metals (Fe, Co and Ni) multilayered were polarized by the neighboring ferromagnetic atoms, and the magnetic behaviors of the three multilayers were different in three systems.

Boron-doped polycrystalline diamond thin films may have some use in electroanalysis since the doped diamond films are electrically conductive and chemically inert. In order to use the boron doped diamond thin films as an active electrode in sensors, we have investigated properties of the boron doped diamond thin films grown on silicon substrates by hot-filament assisted chemical vapor deposition (CVD) using a gas mixture of methane and hydrogen. As-deposited films were characterized by Raman spectroscopy and scanning electron microscopy for their chemical nature and morphology, respectively. In situ doping of boron was achieved by heating H₃BO₃ powder during the deposition. The electrochemical behavior of the boron doped diamond thin film electrodes were investigated using cyclic voltammetry. A reduction peak of Fe³⁺ was observed. Our results show that the boron doped diamond thin films possess suitable properties of an electrode material for use in sensors.

Polymer (C₆H₅C)_n, (i.e. (RC)_n, R equals Ph equals Phenyl), synthesized by chemical reaction, is a pyrolytic precursor to carbon. The carbon-based network backbone structure in polymer, under pyrolysis, could be converted to hard, abrasive and highly reflective solid. The powder of this solid can easily scratch glass and quartz plates. After pyrolysis, the films, coated by using (RC)_n on various substrates Si, silica, Al₂O₃, exhibit linear temperature-dependence property of its electrical surface resistance. By SEM, diamond crystallites with grain size from several tens nanometers to several microns have been observed. It proves that under heat decomposition, carbon-based network backbone structures have converted to sp³- bonded carbon phases.

Polycrystalline diamond films have been deposited onto Si₃N₄-coated silicon substrates using thermal chemical vapor deposition (CVD). The defects on the amorphous layer played an essential role in diamond nucleation. After the deposition, very few diamond crystallites were found on the untreated Si₃N₄ coating, while a diamond film had been formed on the ultrasonically treated Si₃N₄ coating with diamond powder. The adhesion of diamond film to Si₃N₄-coated Si substrates was stronger than that of diamond film to Si substrate and decreased as the CH₄ concentration increased. The erosion resistance of diamond film on Si₃N₄-coated Si substrate was much stronger than that of Si₃N₄ film on Si substrate.

Based on the hydrodynamical model, we develop a transfer matrix formalism to study the optical properties of a superlattice which is composed of two alternating conducting slabs and is subjected to an external static magnetic field parallel to the interfaces. The retardation and collisional damping effects are taken into account. We present the dispersion relations of the electromagnetic modes for an infinite periodic structure and calculate the reflection spectra for a finite system. The localization of the polaritons in a quasi-periodic multilayers is discussed by plotting the amplitudes of the electric field. We find that the dispersion relations are obviously modified by the external magnetic field, and the reflection spectra show rich structure when the magnetic field is applied. The spectra of the electromagnetic modes for the quasi-periodic multilayers exhibit a Cantor-like structure with a scaling property. A transition of extended states to localized states is possible when we vary the applied magnetic field.

Large area high quality diamond films have been synthesized at growth rate of 0.5 approximately equals 2 micrometers /hr by AHFCVD method. Many important improvements have been made compared with conventional HFCVD. With this technique, it is possible to produce high quality diamond films on substrate as large as 15 cm X 15 cm in size at higher growth rate.

In synthsis of diamond thin film by Hot Filment Chemical Vapor Deposition (HF-CVD), many factors can affect diamond nucleation. The mechanical pretreatments, scratching with diamond paste or ultrasonic irradiation with diamond powder suspensions, and the chemical pretreatment, such as erosion with a solution of HF-HNO₃, can create many defects on the surface of silicon substrate and promote the diamond nucleation density. Also, diamond nucleation density can be promoted with carbide intermediate layer of diamond-like carbon film on polished silicon substrate. Diamond nucleation can be varied with different deposition parameters, among the deposition parameters, CH₄/H₂ ratio and substrate temperatures influence the diamond nucleation effectively.

We deposited the diamond film on amorphous diamond film surface. The film has uniform smooth surface. The nucleation density was increased.

Metal oxide films have been successfully prepared from carboxylate, alkoxide, mixed alkoxide/carboxylate precursors. The formation of molecular clusters in these systems offers significant advantages in the preparation of multi-component ceramic thin films, in terms of processing temperature, homogeneity, and stoichiometry control. Alkoxide precursors have been known for network formation in the solution by hydrolysis and polymerization, while carboxylate precursors do not normally show such tendencies. The objective of this work was to study the cluster formation in the carboxylate and mixed alkoxide/carboxylate systems using a variety of analytical techniques, including FT-IR, Mass Spectroscopy, and NMR. Results indicate such clusters do form under controlled conditions, and likewise aid the formation of highly homogeneous films at low temperature. The deposition of oxide films on a variety of substrates from various liquid precursors is becoming a proven technology with attractive possibilities for low cost fabrication. Understanding and control of solution chemistry is critical to its success.

Based on the physico-chemical properties of microcellular polymer foams and the mechanism of porous formation, micro and ultramicro-cellular polyteraflouroethylene porous membranes were prepared by pressure- induced phase separation in a supercritical fluid solution film. The samples were inspected by scanning electron microscope, electron spectroscopy for chemical analysis, differential scanning calorimeter and blowing bubble method. The results show that the membranes prepared by pressure-induced phase separation and then combining with plasma polymerization with ethylene, are easier to control with better characteristics.

An amperometric glucose biosensor was fabricated by the electrochemical polymerization of aniline onto a gold electrodes in presence of glucose oxidase in phosphate buffer solution, pH 7.0. Aniline is easily polymerized forming a thin film, which adheres tightly on the electrodes surface. During the electropolymerization process the enzyme was entrapped into the polyaniline film being able to catalyze the hydrolysis of glucose. The experiments were performed to determine the optimal condition for polyaniline-glucose oxidase film preparation. Glucose can be determined by the biosensor in the concentration range 10^-4 M to 2 X 10^-2 M. The linearity of the biosensor response was observed from 2 X 10^-4 M to 6 X 10^-3 M glucose, which demonstrated that the internal diffusion of substrates and products of reaction through the polyaniline layer to the electrodes surface was the main limiting factor controlling the response value. The method of electropolymerization was found to have several advantage in comparison with other approaches especially for further mass manufacturing of the biosensors.

The noncontact electromagnetic induction method for measuring the transition temperature of large area high Tc films is described. This technique rely on the variation of the mutual inductance between two coils. Our designed system can detect the large area samples which diameter more than 10 mm. In addition, the apparatus can measure many positions on same sample simultaneously by a personal computer. Transition temperature may be measured with a precision of 0.2 K. The temperature range can cover 64-300 K using a platinum resistor as temperature sensor in liquid nitrogen cryostat.

The main research activities of thin film synthesis by ion beam technique in Shanghai Institute of Metallurgy (SIM) are reviewed. Hard and metal alloy coatings, such as TiN, TiBx, SiNx, DLC (diamond like carbon), Pt, and NI/Cr-Ag, are synthesized by ion beam assisted deposition (IBAD) on different kinds of substrates at room temperature. The mechanical, electrical properties and the microstructure of the films were systematically analyzed and discussed with the formation conditions. The experimental result reveals that one of the outstanding characteristic of the IBAD films is the very strong adhesion strength to the substrates. Buried layer formation by ion implantation is one of another newly developed technique. The formation of buried insulating layer in silicon crystal is carried out by high dose O⁺ and N⁺ implantation. Epitaxial growth of high Tc YBCO superconductive thin films on SrTiO₃ is studied by DC magnetron sputtering.

Ferroelectric materials such as lead zirconate titanate exhibit a range of physical properties of interest for different applications in today's technique. They are characterized by high dielectric constants and a permanent, electrically switchable polarization and display strong piezoelectric, pyroelectric and electrooptic effects. In the form of thin films, ferroelectrics can be integrated with existing semiconductor technologies. This opens a variety of possibilities to improve existing devices or to design new microelectronic and micromechanical components and devices such as nonvolatile memory devices, integrated multilayer capacitors, infrared detector arrays, electrooptic switches and modulators, microactuators and motors, integrated pressure and acceleration sensors and bulk acoustic resonator devices.

The interaction of deuterium with tungsten (100) face has been investigated within the temperature range from 4.2 to 900 K by the methods based on galvanomagnetic size phenomena - Sondheimer oscillations. It has been shown that the deuterium deposition at 4.2 K up to the saturation doesn't result in a formation of adsorbate ordered phases, whereas the deposited film annealing is accompanied by deuterium concentration changes and results in a formation of known earlier ordered structures and characteristic changes of oscillation parameters.