Photoluminescence of high-quality AlGaAs layers grown by molecular-beam epitaxy

We report a photoluminescence study of high-purity AlxGa1-xAs layers grown by molecular-beam epitaxy over the 0 less than or equal to x less than or e qual to 0.295 composition range. The intense excitonic line dominates in th e photoluminescence spectra of the layers. The full width at half maximum o f the excitonic line is in excellent agreement with values calculated by Le e and Bajaj [J. Appl. Phys. 73, 1788 (1993)] for perfectly random alloys, a nd in the spectra of the layers with AlAs fractions of x = 0.15 and x = 0.2 09 it equals to 1.24 and 1.48 meV, respectively. A linear dependence of the exciton line intensity on excitation power evidences negligible concentrat ion of nonradiative recombination centers in the layers. (C) 2000 American Institute of Physics. [S0003-6951(00)00209-6].