Abstract
Measurements of photoluminescence (PL), photocurrent (PC), and the Hall-effect have been made on In-doped GaSe. The 1.97 eV peak in the PC spectrum at 295 K is related to the interstitial In atoms. The carrier transport for the Hall-effect measurement is predominated by the acceptor levels at 0.46 eV above the valence band. By comparison with the results of GaSe grown with excess Ga atoms, the acceptor level is considered to be related to the complex center of the interstitial In atom and Se vacancy. We find, from the results of the PL, PC, and Hall effect measurements that the concentration of the defects or defect complexes is very high in In-doped GaSe.