Impact ionization threshold energy of trigonal selenium: An ab initio study1

摘要: Impact ionization coefficient is a critical parameter that determines the multiplication gain in avalanche photodiodes. The impact closely related to threshold, Eth, which determined by band dispersion of semiconducting material used detectors. threshold energy commonly calculated based on parabolic assumption, provides only crude approximation. Here we present first principle study through an analysis electronic structure trigonal selenium. It shown excess primary charge carriers required initiate selenium can be as low gap, Eg, sharp contrast approximation implies Eth = 3/2Eg. Such value favourable factor for ionization.