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Title: Optical and structural characterization of GaN thin films at different N to Ga flux ratios

Abstract

GaN films were grown on Si(111) substrates under various beam equivalent pressure (BEP) ratios by plasma-assisted molecular beam epitaxy. The optical properties for the grown samples were studied over a wide spectral range from 200 to 3300 nm using the reflectance spectrum only. It was found that increasing the N/Ga BEP ratio from 17.9 to 46.1 increases the refractive index (n) from 2.05 to 2.38 at wavelength 630 nm (for example), while the optical energy gap (E{sub g}) were found to be in the range between 3.325 to 3.35 eV with no specific trend. The structural properties for the grown films were studied through two types of rocking curve measurements; normal rocking curve ({omega}-scan) and triple axis rocking curve ({omega}/2{theta}-scan). It was found that with decreasing the N/Ga ratio from 46.1 to 17.9 the full width at half maximum decreases from 0.62 deg. to 0.58 deg. for {omega}-scan and from 0.022 deg. to 0.021 deg. for {omega}/2{theta}-scan. Thus, our results showed a clear correlation between the optical-structural parameters and the BEP ratios of N and Ga.

Authors:
 [1]
  1. Department of Physics and Astronomy, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)
Publication Date:
OSTI Identifier:
21538046
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 109; Journal Issue: 2; Other Information: DOI: 10.1063/1.3534001; (c) 2011 American Institute of Physics; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BEAMS; CHARGES; CHEMICAL VAPOR DEPOSITION; CORRELATIONS; ENERGY GAP; GALLIUM NITRIDES; MOLECULAR BEAM EPITAXY; NEUTRON DIFFRACTION; OPTICAL REFLECTION; PLASMA; REFRACTIVE INDEX; SEMICONDUCTOR MATERIALS; SILICON; SPECTRA; SUBSTRATES; THIN FILMS; WAVELENGTHS; CHEMICAL COATING; COHERENT SCATTERING; CRYSTAL GROWTH METHODS; DEPOSITION; DIFFRACTION; ELEMENTS; EPITAXY; FILMS; GALLIUM COMPOUNDS; MATERIALS; NITRIDES; NITROGEN COMPOUNDS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; PNICTIDES; REFLECTION; SCATTERING; SEMIMETALS; SURFACE COATING

Citation Formats

El-Naggar, Ahmed M. Optical and structural characterization of GaN thin films at different N to Ga flux ratios. United States: N. p., 2011. Web. doi:10.1063/1.3534001.
El-Naggar, Ahmed M. Optical and structural characterization of GaN thin films at different N to Ga flux ratios. United States. https://doi.org/10.1063/1.3534001
El-Naggar, Ahmed M. 2011. "Optical and structural characterization of GaN thin films at different N to Ga flux ratios". United States. https://doi.org/10.1063/1.3534001.
@article{osti_21538046,
title = {Optical and structural characterization of GaN thin films at different N to Ga flux ratios},
author = {El-Naggar, Ahmed M},
abstractNote = {GaN films were grown on Si(111) substrates under various beam equivalent pressure (BEP) ratios by plasma-assisted molecular beam epitaxy. The optical properties for the grown samples were studied over a wide spectral range from 200 to 3300 nm using the reflectance spectrum only. It was found that increasing the N/Ga BEP ratio from 17.9 to 46.1 increases the refractive index (n) from 2.05 to 2.38 at wavelength 630 nm (for example), while the optical energy gap (E{sub g}) were found to be in the range between 3.325 to 3.35 eV with no specific trend. The structural properties for the grown films were studied through two types of rocking curve measurements; normal rocking curve ({omega}-scan) and triple axis rocking curve ({omega}/2{theta}-scan). It was found that with decreasing the N/Ga ratio from 46.1 to 17.9 the full width at half maximum decreases from 0.62 deg. to 0.58 deg. for {omega}-scan and from 0.022 deg. to 0.021 deg. for {omega}/2{theta}-scan. Thus, our results showed a clear correlation between the optical-structural parameters and the BEP ratios of N and Ga.},
doi = {10.1063/1.3534001},
url = {https://www.osti.gov/biblio/21538046}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 2,
volume = 109,
place = {United States},
year = {Sat Jan 15 00:00:00 EST 2011},
month = {Sat Jan 15 00:00:00 EST 2011}
}