Optical properties improvement of GaSb epilayers through defects compensation via doping

The optical properties of GaSb strongly depend on the defect types and concentration. Doping is an effective method to improve the optical properties by changing the native defect types and concentration. In this paper, the native defects related emissions were suppressed through defects compensation via Be-doping. The un-doped and Be-doped GaSb were fabricated by molecular beam epitaxy. Temperature- and excitation power-dependent photoluminescence were applied to investigate optical properties of GaSb epilayer. The Ga vacancy related emission disappeared after Be doping. This phenomenon can be explained by the defect compensation between Be atoms and Ga vacancy, which greatly reduced the concentration of native defects. To certify this theory, Te-doped GaSb was prepared. For Te-doped GaSb, TeSb recombined with native defects and formed new complex defects, which enhanced the defects related emission peak. The investigation of optical properties of doped GaSb epilayer was great significant for practical application of GaSb-based devices.