PHOTOCONDUCTIVITY STUDIES OF GALLIUM SESQUISULFIDE SINGLE-CRYSTALS

Photoconductivity studies were carried out on Ga2S3 single crystals pr epared from melt. We studied the effect of light intensity, applied vo ltage, and ambient temperature on both the spectral distribution of ph otoconductivity and the lifetime of carriers. We found that the mode o f the spectral characteristics was practically independent of the ligh t intensity and applied bias voltage, but shifted to higher values of the photocurrent with increase light intensity and applied bias voltag e. It was also noticed that the photocurrent decreases with the increa se of temperature up to 200 K and increases above this temperature. Th e (E(g)-T) behaviour was in agreement with behaviour described by the Varshni equation; its constant was found to be alpha = 6.021 x 10(-4) eV K-1, beta = -167 K and the temperature coefficient dE(g)/dt = -5.33 x 10(-4) eV K-1. It was shown that the lifetime tau decreases with an increase of light intensity and applied voltage, increases with a dec rease in temperature and, below 200 K, the lifetime decreases with an increase in temperature.