Ultrahigh quantum efficiency of CuO nanoparticle decorated In 2Ge2O7 nanobelt deep-ultraviolet photodetectors

Abstract

Although there has been significant progress in the fabrication and performance optimization of 1-D nanostructure-based deep-ultraviolet photodetectors, it is still a challenge to develop an effective device with high performance characteristics, such as high photocurrent-dark current ratio and high quantum efficiency. Herein, an efficient and simple method to fabricate high performance CuO nanoparticle decorated In<inf>2</inf>Ge<inf>2</inf>O <inf>7</inf> nanobelt deep-ultraviolet photodetectors is presented. A CuO coated In<inf>2</inf>Ge<inf>2</inf>O<inf>7</inf> nanobelt based photodetector showed very high responsivity (7.34 × 10⁵ A W^-1) and high quantum efficiency (3.5 × 10⁶). The underlying mechanism is proposed to be the formation of p-n heterojunctions between decorated nanoparticles and nanobelts, which enhances the spatial separation of photogenerated electrons and holes. This study opens up a new horizon for creation of novel photodetectors with high quantum efficiency. © 2012 The Royal Society of Chemistry.