MBE GROWTH OPTIMIZATION AND THERMAL-STABILITY OF STRAINED IN0.25GA0.75AS LAYERS IN MODFET LAYER STRUCTURES

We have grown by MBE a series of MODFET structures containing In.25Ga.75As channel layers. The channel layer thickness and MBE growth conditions (growth temperature and V/III ratio) have been optimized in order to achieve mobilities as high as possible. The structures were characterized by Hall and low temperature photoluminescence measurements. Non optimized growth conditions cause a degradation of the carrier mobility and give rise to an additional peak in the PL spectrum in parts of the wafer. We have performed rapid thermal annealing experiments and have studied the dependence of the PL spectrum on the annealing temperature.