Alloy disorder effects in III–V ternaries studied by modulation spectroscopy

Modulation spectroscopy has been applied to several III–V ternary alloys, grown by MBE. Thermal disorder caused by the exciton—LO phonon interaction at room temperature is treated along with alloy disorder in a universal way by assuming a Gaussian absorption profile. A linewidth analysis shows that, in some cases, the presence of inhomogeneous composition variations on a scale of about 7–15 Å dominate the spectra. The latter implies that non-random alloys can be grown by MBE.