A stressed Ge:Ga photoconductor array with three elements applied to the Infrared Telescope in Space satellite was fabricated and tested in experiments at 2.0 K in very low-photon-influx conditions (~105 photons/s). Stress was applied to three Ge:Ga detectors in a series by a stable and compact stressing apparatus by using cone-disk springs. The cutoff wavelength was ~180 μm. Responsivity was ~100 A/W, and the product of quantum efficiency and photoconductive gain, ηG, was ~1 with a chopping frequency of 2 Hz. The noise equivalent power was <5 × 10−18 W/Hz1/2 when low-noise transimpedance amplifiers were used. A slow transient response and a nonlinear response that was dependent on the background photon influx were observed in the experiments. The latter showed that the ηG had a time constant τc that was proportional to Nph−1/2.
© 1992 Optical Society of America
Original Manuscript: September 28, 1990
Published: February 1, 1992
N. Hiromoto, T. Itabe, H. Shibai, H. Matsuhara, T. Nakagawa, and H. Okuda, "Three-element stressed Ge:Ga photoconductor array for the infrared telescope in space," Appl. Opt. 31, 460-465 (1992)