Quantum efficiency coefficient for photogeneration of carriers in gallium sulphide single crystals

This paper presents investigations of the quantum efficiency coefficient for the photogeneration of carriers in gallium sulphide (GaS) single crystals. Therefore the spectral dependences (between 420 and 550nm) of photoconductivity (σ_PC) were measured for temperatures from 80 to 333K and for different light intensities. Since σ_PC depends on the absorption and reflection coefficients, these parameters were determined in the same range of temperatures. The least-squares method was applied to fit the experimental σ_PC data with appropriate theoretical dependence. From this fitting, spectral dependences of quantum efficiency coefficients for different temperatures and different light intensities were obtained. A comparison of the values of absorption coefficient obtained from the measurements of optical transmittance and from evaluation of the quantum efficiency coefficient is presented.