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Proceedings Paper

Near-infrared electroluminescence of furnace or CO2 laser annealed Si-rich SiO2 with structural defects and Si nanocrystals
Author(s): Gong-Ru Lin; Chun-Jung Lin
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Paper Abstract

Electroluminescence of the CO2 laser annealed PECVD-grown silicon-rich silicon oxide (SRSO) based metal-oxide-semiconductor diode with embedded Si nanocrystals is demonstrated. The structural and optical properties of a CO2 laser rapid thermal annealed Si-rich SiO1.25 film are investigated. The color of SiO1.25 film changes from light yellow to dark-yellow as the CO2 laser annealing intensity enlarges from 1.5 to 13.5 kW/cm2. Such a color change is mainly attributed to both the increasing absorption coefficient and refractive index of the SiO1.25 film under the precipitation of Si nanocrystals. The thickness of the SiO1.25 film was thinned during the dehydrogenated process at a slightly lower laser intensity of 4 kW/cm2, while the complete dehydrogenation is observed after annealing for 1.4 ms associated with a thickness shrinking from 280 nm to 240 nm. TEM analysis and photoluminescence spectroscopy at 806 nm reveal that the Si nanocrystals with maximum diameter and density of 5.3 nm and 1018 cm-3, respectively, can be precipitated as the CO2 laser intensity increase to an ablation threshold intensity of 5.8 kW/cm2. The laser ablation introduces numerous structural defects and causes the anomalous absorption as well as photoluminescence at blue-green wavelengths in the SiO1.25 film. From the reflection spectra with enlarged interfering fringe amplitude, the increasing refractive index (from 1.57 to 1.88) of the SiO1.25 with increasing laser intensity can be concluded. In comparison with that of the quartz or as-grown sample, the red-shifted optical bandgap energy of the CO2 laser-annealed SiO1.25 film from 5.4 eV to 4 eV has evidenced the effect of the strong blue-green absorption on the oxygen vacancy defect. The forward turn-on voltage and current density of the ITO/CO2 laser annealed SRSO/p-Si/Al MOS diode are 79 V and 33 μA/cm2, respectively. The maximum output power of 29 nW associated with a P-I slope of 4.4 mW/A is determined.

Paper Details

Date Published: 20 April 2006
PDF: 11 pages
Proc. SPIE 6195, Nanophotonics, 619515 (20 April 2006); doi: 10.1117/12.663184
Show Author Affiliations
Gong-Ru Lin, National Chiao Tung Univ. (Taiwan)
Chun-Jung Lin, National Chiao Tung Univ. (Taiwan)

Published in SPIE Proceedings Vol. 6195:
David L. Andrews; Jean-Michel Nunzi; Andreas Ostendorf, Editor(s)

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