Forward and reverse electron transport properties across a CdS/Si multi-interface nanoheterojunction

Abstract

The electron transport behavior across the interface plays an important role in determining the performance of optoelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole—Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of interfacial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.