GROWTH-STUDIES OF (AL,GA,IN)AS ON INP BY MOLECULAR-BEAM EPITAXY

We have investigated the influence of growth temperature and growth in terruptions on the optical properties of (Al,In)As, (Ga,In)As and (Al, Ga,In)As lattice-matched to InP substrates. Heterostructures and bulk material samples were analyzed by photoluminescence, X-ray spectroscop y, transmission electron microscopy and optical microscopy. The best o ptical properties are achieved at different growth temperatures, depen ding on the material composition. This temperature varies between 460- degrees-C for (Ga,In)As and 530-degrees-C for (Al,In)As. Photoluminesc ence studies of quantum well (QW) samples show that heterointerfaces g rown from (Ga,In)As to (Al,In)As are very sensitive to growth stops, w hile there is no significant influence if the growth stop is made afte r growth of (Al,In)As. Laser structures with three QWs made from that material system reach threshold current densities for infinitely long cavities as low as 120 A/CM2 per QW for an emission wavelength of 1.7 mum and 260 A/cm2 per QW for 1.3 mum.