Far-Infrared Germanium Detectors

Abstract

Two types of far-infrared Ge detectors have been investigated. One is a photoconductivity-type detector, utilizing photo-excitations from the shallow donors (Sb) or acceptors (In) in Ge. The impurity concentration of this type in the range from 6×10 14 cm -3 to 5×10 15 cm -3 . These detectors exhibit photoresponse over the wavelength region of 50∼120 µ and their response-time is less than 1 µsec. The other detector is of bolometer type, making use of energy absorption by the free carriers of the impurity conduction. The concentration of In impurity is about 7×10 16 cm -3 . The detector of this type has a photoresponse over the wavelengths of 20∼1000 µ and the response-time is about 300 µsec.