Photoreflectance of GaSb/Al0.4Ga0.6Sb single quantum wells

We report a photoreflectance study conducted in the 0.7-1.2 eV photon energ y range and at temperatures from 80 to 300 K of GaSb/Al0.4Ga0.6Sb single qu antum wells grown by molecular beam epitaxy. We observed clear and well-res olved structures, which could be attributed to the interband optical transi tions originating in both the GaSb buffer and the quantum wells, and which could be fitted by standard critical-point line shapes. Our results demonst rate that even unintentionally doped GaSb-based quantum systems can be stud ied and characterized by photoreflectance, especially at low temperatures. (C) 1998 American Institute of Physics, [S0003-6951(98)00235-6].