Spectroscopic study of surfactant enhanced organometallic vapor phase epitaxy growth of GaInP

Samples of GaxIn1-xP grown by organometallic vapor phase epitaxy on (001) G aAs substrates by addition of TESb demonstrating a lateral superlattice com positional modulation (CM) have been studied by low temperature polarized p hotoluminescence (PL), power dependent PL, and photoluminescence excitation (PLE) spectroscopy. Strong polarization is observed in the low temperature PL and PLE spectra at Sb concentrations below that where CuPtB ordering is removed and triple period ordering is produced. Low temperature polarized PL is shown to be the most sensitive optical technique for detecting the pr esence of CM. The radiative recombination mechanism at low temperature is e xcitonic, originating from the exponential tail of band gap states observed in the PLE spectra. From the measured band gaps, a continuum model of the band structure allows an estimate of an upper limit of the percent modulati on present in the samples. Above Sb/III(v)=0.01, compositional modulation i s the dominant factor determining the low temperature optical properties. T he percent fluctuation of composition increases monotonically with increasi ng Sb during growth. (C) 2001 American Institute of Physics.