GAAS/ALGAAS QUANTUM-WELL STRUCTURES GROWN BY GAS-SOURCE MBE USING TEG, TEA, AND ASH3

We have studied the atomic steps and terraces at the interfaces of GaAs/AlGaAs single quantum well (SQW) structures grown by gas-source MBE on slightly misoriented GaAs substrates from (100) toward (111)A or (111)B plane with various misorientation angles α=0°, 0.5°, 1°, 2°, 4°, and 6°. The full-width-at-half-maximum of the photoluminescence (PL) peak from a gas-source MBE-grown QW having a well width of 1.4 nm on (100) flat substrates coincides with the calculated value, considering one-monolayer well-width fluctuation. We found that the 77 K PL linewidth of the QWs grown on (111)A-misoriented substrates decreases with increasing misorientation angle, and that, conversely, that of QWs grown on (111)B-misoriented substrates increases when the QWs were grown at a substrate temperature of 650°C. It was suggested that the heterointerface on (111)A-misoriented substrates consists of straight and regularly spaced steps, while that on (111)B-misoriented substrates consists of rough step edges, randomly spaced with step heights of several monolayers. © 1990.