MOLECULAR-BEAM EPITAXIAL-GROWTH OF HIGH-QUALITY INALAS ON INP (100) SUBSTRATES AT VERY HIGH ARSENIC PRESSURES

We report in this letter the molecular beam epitaxial (MBE) growth of In(0.52)Ab(0.48)As on InP (100) substrates at very high arsenic overpr essures and their characterisation using low temperature photoluminesc ence (PL) and X-ray diffraction (XRD). The effect of the high arsenic overpressures on the optical quality and lattice-mismatch in the In(0. 52)Ab(0.48)As material were investigated. Within the range of the V/II I flux ratios investigated (32-266), our results show for the first ti me that very high arsenic overpressures during MBE growth have no detr imental effect on the quality of the InAlAs, in contrast to the genera lly believed crystalline degradation due to the adverse effect on the cation surface mobilities. There is also an insignificant effect on th e quality of the heterointerface as the lattice-mismatch was relativel y insensitive to flux ratio variations within the range investigated. A significant improvement in the uniformity of the PL peak energy was also observed.