Al0.3Ga0.7As/GaAs single quantum well structures grown by molecular beam epitaxy on misoriented substrates

In many instances the intrinsic photoluminescence at low temperatures of (Al,Ga)As/GaAs single quantum well structures grown by molecular beam epitaxy is weak and broad, unlike the case for most multiple quantum well structures. This is believed to be due to the microscopic roughness of the first GaAs-on-top-of-(Al,Ga)As interface. By using substrates misoriented appropriately from nominal (100) such that Al0.3Ga0.7As barrier layers with smooth surface morphology could be obtained at a growth temperature of 650 °C, we have grown structures with a single 100-Å-wide GaAs well. The structures grown on misoriented substrates showed stronger and sharper (as narrow as 1.8 meV) intrinsic emission peaks at 4.2 K. The improvement is believed to be due to the growth of smoother interfaces.