Photoelectronic properties of n-GaSe

Electron and hole trapping centres of GaSe(I2) grown by chemical transport method are investigated by using photoelectronic techniques, such as thermally stimulated current (TSC), thermal quenching of photoconductivity (TQ) and spectral response of photoconductivity. Several electron trapping centres, between 0.15 and 0.65 eV below the conduction band, with densities ranging from 1013 to 1016 cm−3 and capture cross-sections between 10−13 and 10−19 cm−2 are found. Three hole trapping centres, acting as sensitizing centers for photoconductivity, are also present at 0.40, 0.27, and 0.21 eV above the valence band. They are responsible for a superlinearity in the behaviour of the photocurrent versus light-intensity at low temperature.