The process of charge carrier generation in photosensitive elements based on heterojunction of monocrystalline and amorphous silicon

Abstract

In this article, to describe the process of charge carrier generation and current transfer, we consider a model for calculating the characteristics of photovoltaic cells based on heterojunctions of amorphous - monocrystalline silicon in the kinetic approximation. Developed the main provisions of a numerical model for the study, based on the statistics of the broken bonds, and physics of photogeneration and sign conclusion nonequilibrium carriers, and the experimental verification of the obtained simulation results. The use of a simplified model of the density of states in the mobility gap of hydrogenated amorphous silicon is substantiated. This model allows to carry out researches of influence of temperature, degree of alloying and the geometrical sizes on characteristics of photoconverters. The generation of current carriers is characterized by the rate of optical generation and for the interpretation of photoconductivity, the following models of recombination are used such as zone-tail, which occurs when a nonequilibrium carrier is captured from the free zone to the tail state of the opposite zone, which has captured the carrier of another sign and acts as a recombination center. The number of tail states increases as the temperature decreases. Tail - broken link recombination occurs when captured carriers are tunneled from the tail zone state to the broken link state. The dependence of the photoconductivity on the temperature of these structures is calculated.