Photo-induced current transient spectroscopy of Al0.48In0.52As semi-insulating layers grown on InP by molecular beam epitaxy

Deep levels in undoped semi-insulating In0.52Al0.48As layers grown by molecular beam epitaxy on iron-doped InP have been studied by photoluminescence and photo-induced current transient spectroscopy. The effect of the growth temperature Tg in the range from 300 °C to 530 °C has been investigated. The results show that low Tg causes the material quality to deteriorate and leads to formation of a higher concentration of deep traps. It is shown that optimized material quality can be obtained for InAlAs layers on InP substrates with Tg around 530 °C with sufficiently high resistivity, reduced trap density and good structural properties which is appropriate for fabrication of high electron mobility transistors.