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Proceedings Paper

Far-infrared characterization of GaN epilayers
Author(s): G. Mirjalili; Terence J. Parker; Tin S. Cheng; C. Thomas Foxon; John W. Orton
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Paper Abstract

The far infrared optical properties of a selection of thin epitaxial layers of GaN deposited on GaAs substrates by molecular epitaxy (MBE) have been studied by polarized oblique-incidence reflection spectroscopy at 77 and 300 K. The epilayers were grown in the cubic ((beta) -GaN) and wurtzite ((alpha) -GaN) phases. The vibrational and electronic properties of the samples have been determined by using standard optical transform matrix method to fit computed reflectivity spectra of the layered samples to the measured spectra. The model was extended to deal with anisotropic dielectric functions to account for the phonon and plasmon responses of (alpha) -GaN. In s-polarized measurements, the bulk plasma response gives direct information on the free carrier dynamics in the plane of the epilayer. The normal componento f the free carrier dielectric response couples strongly to Brewster and Berreman interface modes at frequencies close tot he LO phonon frequency. In p-polarization measurements, these interface modes have been observed and assigned with the aid of dispersion curve calculations. It is shown that Brewster and Berreman interface modes can be used to characterize the structural and electronic properties of the samples.

Paper Details

Date Published: 8 March 2001
PDF: 8 pages
Proc. SPIE 4318, Smart Optical Inorganic Structures and Devices, (8 March 2001); doi: 10.1117/12.417585
Show Author Affiliations
G. Mirjalili, Univ. of Essex and Univ. of Yazd (United Kingdom)
Terence J. Parker, Univ. of Essex (United Kingdom)
Tin S. Cheng, Univ. of Nottingham (United Kingdom)
C. Thomas Foxon, Univ. of Nottingham (United Kingdom)
John W. Orton, Univ. of Nottingham (United Kingdom)


Published in SPIE Proceedings Vol. 4318:
Smart Optical Inorganic Structures and Devices
Steponas P. Asmontas; Jonas Gradauskas, Editor(s)

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