Giant photoelectric energy conversion via a 3C-SiC Nano-Thin film double heterojunction

Abstract

Enhancing the energy conversion efficiency is utmost important in renewable energy and self-powered optoelectronic sensing applications. In this study, we propose the concept of a p-3C-SiC nano-thin film/p-Si/n-Si double junction (DJ) structure, which exhibits a massive photoelectric energy conversion efficiency and ultra-high sensitivity of optoelectronic sensors. The optoelectronic characteristics of this DJ heterostructure are compared to those of a p-3C-SiC/n-Si single-junction (SJ) heterostructure, which shares similarities in all technical and material parameters, except for the inclusion of the middle p-Si layer in the DJ structure. The experimental results reveal that the lateral photocurrent, sensitivity, theoretical power and maximum power of the DJ structure are more than 100 times (i.e. over 10,000%) greater than those of the SJ structure. We then demonstrated these excellent features of DJ heterostructure through developing of a self-powered position sensitive sensor, which showed an ultrahigh sensitivity. The enormous enhancement in the performance has been elucidated through the efficient photogeneration of charge carriers, electron-hole pair splitting, and the improved charge carrier transport mechanisms in the double heterojunction. This research represents a notable breakthrough in ultra-sensitive optoelectronic sensors and photoenergy conversion, since the proposed concept and theoretical model can be extended to multiple junctions of various semiconductor materials.