The far-infrared optical constants, quantum efficiency and internal quantum yield of detector-quality gallium-doped germanium

Abstract The temperature variation of the optical constants of detector quality gallium doped germanium have been determined between 4.7 and 295 K in the spectral region from 30 to 130 cm −1 . The 4.7 K absorption and refraction spectra were used to calculate the expected quantum efficiency of a Ge:Ga photoconductor having similar geometric and electrical characteristics to those used in earlier detector studies. A comparison of this with measurements of the photoconductive response of such a detector allowed the spectral variation of the internal quantum yield of photoexcited free carriers to be studied.