Properties of GaAs/AlGaAs quantum wells grown by MOVPE using vicinal GaAs substrates

摘要

Low-temperature photoluminescence (PL) was used to optimize the structural and optical quality of 2-15 nm thick GaAs/AlGaAs quantum wells (QWs). GaAs wafers, misoriented off(1 00) towards < 1 1 1 > A and < 1 1 1 >B were used, covering the 0-0.6° misorientation range in steps of 0.1°. A dramatic reduction in the 10 K PL linewidth is observed for all 0.2-0.3° misorientations, as compared to nominally oriented wafers: on 2, 5 and 15 nm thick QWs, linewidths fall from 23, 8 and 3 meV to 6, 3 and 2.5 meV, respectively, among the narrowest reported to date for similar structures. Above 0.3° misorientation, the emission broadens to become, at 0.6°, comparable or worse than for the exact (100) samples. The 4 K electron mobility of two-dimensional electron gases grown on similar, misoriented substrates increases steadily and then decreases again at larger misorientations.