Enhancing Responsivity and Detectevity of Si-ZnO Photodetector With Growth of Densely Packed and Aligned Hexagonal Nanorods

Abstract

High-performance photodiodes are desirable forultrahigh speed optical communication and highresolution optical instrumentation. This paper reports both theoretical and experimental optimization approaches for low-cost chemothermal growth of hexagonal nanorods on Si-ZnO heterojunction. The alignments of nanorods were made by controlling the etching rate with the addition of 2% isopropyl alcohol during the process. The formation of nanorods were found to be linear, densely packed, and uniformly distributed on ZnO thin film as seen from SEM images and X-ray Diffraction (XRD) pattern. The X-ray Photoelectron Spectroscopy result shows the absence of carbon contamination and confirms the elemental composition of ZnO. The current-voltage measurement confirms ohmic junction between the nanostructure and ZnO thin film enhancing the increase of photocurrent, which provides high responsivity. The proposed fabrication process opens up the possibility of realization of low-cost, high-performance, and future flexible optoelectronics sensor circuitry.