We studied the photoemission process in films of amorphous Ge deposited on silica substrates. We measured, for both polarizations and for several angles of incidence, with direct and back illumination (through the substrate), the reflectance, the transmittance, and the photoemissive yield of each film without exposure to air. We analyzed the possibility of deducing with minimum error, from the experimental results, the index of refraction, the thickness, and the escape probability of photoexcited electrons and we verified the validity of the model used for computation.
PIERRE J. VERNIER, JEAN-PIERREG GOUDONNET, GÉRARD CHABRIER, and JEAN CORNAZ, "Optical and Photoelectrical Properties of Amorphous Germanium Films," J. Opt. Soc. Am. 61, 1065-1076 (1971)