on the Photo p The Effects of Deep Levels Optical Emissions of Free Carriers on the Photo-Responses of p-type Silicon (Si)

Abstract

In this study, the effects of deep levels optical emissions of free carriers on the photo-response of silicon (Si) is investigated through the simulation of excess carrier traps corresponding to the non-radiative recombination mechanism. First, the trapping effects (the ratio of the concentration of trapped photo-emitted carriers to the corresponding concentration of free excess carriers in the corresponding bands) is described as a function of localized state energy at room and different temperatures inside the sample. Then, the Shockley-Read-Hall recombination mechanisms are computed using the relations describing the SRH lifetimes and, the lifetimes of the excess majority and minority carriers in the band gap of semiconductor (Si). Finally, the temperature, injection and, localized state density and doping level dependences of the Shockley-Read-Hall lifetimes in the localized regions are investigated by considering the variation of localized energy positions. Since the trapping effect is highly related to the temperature, the description of the trapping effect as functions of localized state energies at various temperatures is found to be the important. The analysis of the results also shows that, the trapping effects are divided into 5 parts based on the interaction of localized state with the conduction band energy and the valance band energy. In general, the trap in shallow levels (donor and acceptor regions) tends to zero and deep levels are dominated. When all the localized states are illuminated at the same rates, the SRH excess carrier lifetimes for excess carriers (for both electrons and holes) increase with increasing the shallowness of the localized states. The deep level SRH lifetimes for minority carriers is highly affected by the trapping effect of the localized states. The shallow level SRH-lifetimes for free holes are not affected by t