Abstract

A solid-state device capable of continuous detection of individual photons in the wavelength range from 0.4 to 28 μm has been demonstrated using arsenic-doped silicon. Operated with a do applied bias, the device responds to the absorption of an incident photon with a submicrosecond rise-time current pulse with amplitude well above the electronic readout noise level. A counting quantum efficiency of over 30% has been demonstrated at 20 μm and over 50% was observed in the visible light region. Optimum photon-counting performance occurs between 6 and 10 K and for count rates of <10¹⁰ counts/s per cm² of detector area. Operation of the device relies on impurity band conduction. Extremely fast internal charge amplification by impact ionization of impurity-band electrons results in a pulse of nearly equal amplitude for each photogenerated carrier. These devices are in effect avalanche photodiodes. However, impurity-band to conduction-band impact ionization is utilized rather than the usual valence-band to conduction-band impact ionization employed in other devices.

© 1987 Optical Society of America