Effect of incorporation of zinc sulfide nanoparticles on carrier transport in silicon nanowires

We investigate the transport properties of silicon nanowires coated with zinc sulfide nanoparticles. Silicon nanowires were prepared by metal assisted electro-less chemical etching technique. The diameter of nanowires varies from 30 to 300 nm and length was similar to 30 mu m. Zinc sulfide nanoparticles having diameter similar to 30 nm were synthesized by co-precipitation method. The nanoparticles were then deposited between the nanowire arrays and most of the nanoparticles stick to the surfaces of the nanowires. The JV characteristics of the devices were investigated from 77 to 300 K. The JV characteristics were nonlinear and asymmetric. The decrease in current density in n-silicon nanowires while increase in current density in p(+)-silicon nanowires were observed when zinc sulfide nanoparticles were coated on them. The decrease in the current density due to the presence of nanoparticles on the walls of the n-silicon nanowires is attributed to enhancement of trapped charge carriers at zinc sulfide nanoparticles and nanowire interface. However increased hole current was observed due to the formation of acceptor like states on the surfaces of p(+)-silicon nanowires when nanoparticles were coated on them. The detailed carriers transport mechanisms were studied in both types of silicon nanowires. With back to back Schottky diode, Schottky emission mechanism was observed in p(+)-silicon nanowires while unusual space charge limited current with and without traps was observed in n-silicon nanowires. (C) 2012 Elsevier B.V. All rights reserved.