Athermalized carrier multiplication mechanism for detectors using an amorphous silicon gain medium.

ABSTRACT

In this paper, we investigate the temperature sensitivity of gain and breakdown voltage of detectors based on cycling excitation process (CEP), an internal signal amplification mechanism found in amorphous silicon (a-Si). Changes in gain and breakdown voltage with temperature can result in pixel-to-pixel signal variation in a focal plane array and variations in photon detection efficiency for single photon detectors. We have demonstrated athermalized CEP detectors with their gain and breakdown voltage being nearly temperature independent from 200 K to 350 K, covering the temperature range for practical applications. The device appears to be more thermally stable than avalanche photodetectors (APDs) with different gain media such as Si, InP, InAlAs, etc. The excellent thermal stability of CEP detectors is attributed to the field-enhanced tunneling process for excitation of localized carriers into the mobile bands, which dominates over the phonon excitation process.