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Optical Spectroscopic Studies of N‐Related Bands in Ga(N, As)
Author(s) -
Grüning H.,
Chen L.,
Hartmann Th.,
Klar P. J.,
Heimbrodt W.,
Höhnsdorf F.,
Koch J.,
Stolz W.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199909)215:1<39::aid-pssb39>3.0.co;2-b
Subject(s) - photoluminescence , spectroscopy , epitaxy , analytical chemistry (journal) , band gap , spectral line , materials science , nitrogen , liquid helium , diffuse reflectance infrared fourier transform , photoluminescence excitation , chemistry , helium , optoelectronics , nanotechnology , physics , catalysis , biochemistry , organic chemistry , layer (electronics) , quantum mechanics , chromatography , astronomy , photocatalysis
We have investigated the unusual band formation at the Γ‐point and in the vicinity of the L‐point in the alloy system Ga(N, As) by various spectroscopic methods. A series of GaN x As 1— x epitaxial layers with x varying from 0.05 to 2.8% was grown on (100) GaAs by metal‐organic vapour phase epitaxy. The samples were studied by photoluminescence (PL) as well as photoluminescence excitation (PLE) spectroscopy, photomodulated reflectance (PR), and conventional reflectance (R) spectroscopy at room temperature and liquid helium temperature. The low‐temperature PL and PLE spectra in the spectral region of the E 0 band gap show clear evidence for in‐gap nitrogen‐pair and cluster states at low concentrations ( x < 0.1%), and for higher nitrogen concentrations the formation of a new band. The dependence of the E 0 band gap on N‐content for x < 1% at 8 K is considerably stronger than at 300 K. Furthermore, R spectra of the E 1 and E 1 + Δ 1 transitions show an uncommonly strong disorder‐induced broadening with increasing N‐content.