Enhanced Optoelectronic and Electrical Properties of Silicon Nanowires by Electrodeposited ZnO Nanoparticles for Efficient Diode Performance

In this paper, Zinc Oxide nanoparticles (ZnO NPs) have been successfully synthesized for the first time by electrochemical deposition on silicon nanowires (SiNWs) produced using silver-assisted chemical etching method. The as-prepared nanowires were pre-coated with ZnO seed layer to initialize the uniform growth of ZnO nanoparticles from aqueous solutions using the electrochemical deposition. The SEM images showed a homogenous distribution of dense ZnO nanoparticles on silicon nanowires. X-ray diffraction pattern indicated that the electrodeposited ZnO NPs have hexagonal wurtzite structure. Current–voltage characteristics pointed that ZnO NPs significantly improved the diode parameters such as ideality factor (n), series resistance ( R s ), energy barrier ( φ b ) and saturation current ( I s ). As a result, a rectifying behavior of the ZnO NPs/SiNWs structure has been exhibited by a factor of 2.7 compared to pure SiNWs structures. The values of the saturation current I s and the series resistance R s of these heterostructures decrease indicating an improvement in junction quality which can be due to the reduction of dangling bonds and surface defects. Significantly, ZnO nanoparticles @SiNWs increased the minority carrier lifetime from 9.11 μ s to 14.89 μ s and consequently reduced the surface recombination activities, further revealing the efficient surface passivation role of ZnO nanoparticles. Good anti-reflectance abilities up to 10% and 15% are observed for pure SiNWs and SiNWs/ZnO NPs, respectively, as compared to 40% for bare Silicon. Based on these findings, SiNWs/ZnO NPs can be considered as potential candidate for optoelectronic devices, photovoltaics and nanoelectronics.