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MBE growth and photoreflectance study of GaAsN alloy films grown on GaAs (0 0 1)

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Bibliographic Details
Title: MBE growth and photoreflectance study of GaAsN alloy films grown on GaAs (0 0 1)
Authors: Nishikawa, A.1 nishikawa@onblab.k.u-tokyo.ac.jp, Katayama, R.1, Onabe, K.1, Shiraki, Y.2
Source: Journal of Crystal Growth. Apr2003, Vol. 251 Issue 1-4, p427. 5p.
Subjects: Thin films, Molecular beam epitaxy, Photorefractive materials
Abstract: The growth condition of GaAsN alloy films has been optimized for higher N contents, and the bandgap energy of the films and its temperature dependence have been investigated by photoreflectance spectroscopy. The GaAsN (N=0−4.5%) alloy films were grown on GaAs (0 0 1) substrates by molecular beam epitaxy equipped with a radio frequency plasma nitrogen source. The As4 flux was varied for the optimization of the growth. The films with a fairly flat surface and high crystal quality were obtained when the As4 flux was close to the V/III ratio of 1. The bandgap energy of GaAsN with the N content of 4.5% was measured as low as 0.93 eV (1.33 μm). In the low (<1%) N content region, the bowing parameter is estimated to be 22 eV. However, the deviation of the experimental data from the fitting curve becomes large as the N content increases due to the composition-dependent nature of the bowing. The temperature dependence of the bandgap energy becomes significantly weak with increasing N content. This suggests that the density of states around the band edge of GaAsN is modified from that of GaAs due to the localized states possibly originated from N clusters. [Copyright &y& Elsevier]
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Database: Engineering Source
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Abstract:The growth condition of GaAsN alloy films has been optimized for higher N contents, and the bandgap energy of the films and its temperature dependence have been investigated by photoreflectance spectroscopy. The GaAsN (N=0−4.5%) alloy films were grown on GaAs (0 0 1) substrates by molecular beam epitaxy equipped with a radio frequency plasma nitrogen source. The As4 flux was varied for the optimization of the growth. The films with a fairly flat surface and high crystal quality were obtained when the As4 flux was close to the V/III ratio of 1. The bandgap energy of GaAsN with the N content of 4.5% was measured as low as 0.93 eV (1.33 μm). In the low (<1%) N content region, the bowing parameter is estimated to be 22 eV. However, the deviation of the experimental data from the fitting curve becomes large as the N content increases due to the composition-dependent nature of the bowing. The temperature dependence of the bandgap energy becomes significantly weak with increasing N content. This suggests that the density of states around the band edge of GaAsN is modified from that of GaAs due to the localized states possibly originated from N clusters. [Copyright &y& Elsevier]
ISSN:00220248
DOI:10.1016/S0022-0248(02)02189-9