Investigation of electronic properties of gallium sulfide single crystals grown by iodine chemical transport

Photoinduced-current-transient-spectroscopy and space-charge-limited-current measurements have been performed on n-type GaS single crystals grown from vapor by iodine chemical transport. Three electron traps located at 0.17, 0.45, and 0.56 eV from the conduction band have been detected, with a thermal capture cross section of 2×10−19, 5×10−14, and 8×10−13 cm2, respectively. Moreover, by Hall-effect measurements, an impurity hopping conduction with an activation energy of 0.12 eV has been evidenced in the range of temperatures between 220 and 320 K.