Optical and Electrical Studies of Electron-Bombarded GaSb

Studies were made on n- and p-type gallium antimonide irradiated with 4.5-MeV electrons. Hall-effect measurements showed that acceptors were produced in the n-type samples and that donors as well as acceptors were produced in the p-type samples. Infrared absorption and photoconductivity studies gave evidence for four defect levels: Eᵥ+0.075 eV, Eᵥ+0.48 eV, Ec- (0.12 to 0.20) eV, Ec- (0.47 to 0.50) eV. The absorption associated with the level Eᵥ+0.075 eV is similar to that observed in donor-compensated GaSb. Previous studies have indicated that such a level is present also in undoped p-type naterial. The present work provides direct evidence that some of the residual "impurities" normally found in GaSb are lattice defects. Carrier capture cross sections have been estimated for the various levels. The values indicate that the level Ec-(0.47 to 0.50) eV is an acceptor level, while the level Ec-(0.12 to 0.20) eV is probably a donor level.