Photodetecting properties of single CuO\u2013ZnO core\u2013shell nanowires with p\u2013n radial heterojunction

Andrei Kuncser,Andreea Costas,Ionut Enculescu,Camelia Florica,Nicoleta Preda

doi:10.1038/s41598-020-74963-4

Andrei Kuncser, Andreea Costas + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-74963-4

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Journal: Scientific Reports	Publication Date: Oct 29, 2020
Citations: 38	License type: open-access

Affiliation: National Institute of Materials Physics

Abstract

CuO–ZnO core–shell radial heterojunction nanowire arrays were obtained by a simple route which implies two cost-effective methods: thermal oxidation in air for preparing CuO nanowire arrays, acting as a p-type core and RF magnetron sputtering for coating the surface of the CuO nanowires with a ZnO thin film, acting as a n-type shell. The morphological, structural, optical and compositional properties of the CuO–ZnO core–shell nanowire arrays were investigated. In order to analyse the electrical and photoelectrical properties of the metal oxide nanowires, single CuO and CuO–ZnO core–shell nanowires were contacted by employing electron beam lithography (EBL) and focused ion beam induced deposition (FIBID). The photoelectrical properties emphasize that the p–n radial heterojunction diodes based on single CuO–ZnO core–shell nanowires behave as photodetectors, evidencing a time-depending photoresponse under illumination at 520 nm and 405 nm wavelengths. The performance of the photodetector device was evaluated by assessing its key parameters: responsivity, external quantum efficiency and detectivity. The results highlighted that the obtained CuO–ZnO core–shell nanowires are emerging as potential building blocks for a next generation of photodetector devices.

Highlights

Given the increasing demand for continuous miniaturization and reduced energy consumption, nanoscale optoelectronic devices based on semiconductor nanowires are emerging as an important novel class of devices with enhanced performances and improved or even new functionalities[1]
The CuO nanowires are vertically grown on the Cu foil, a slight tilt being observed in the case of the CuO–ZnO_2 core–shell nanowires due to the deposition of a thicker Zinc oxide (ZnO) shell
The morphological characterization reveals that the CuO–ZnO core–shell nanowire arrays have a high aspect ratio with diameters of about 80 nm and a thickness of the ZnO shell estimated at ~ 10 nm for CuO–ZnO_1 and ~ 15 nm for CuO–ZnO_2

Summary

Introduction

Given the increasing demand for continuous miniaturization and reduced energy consumption, nanoscale optoelectronic devices based on semiconductor nanowires are emerging as an important novel class of devices with enhanced performances and improved or even new functionalities[1]. Considering all the aspects mentioned above and taking into account the key features provided by the geometry of the radial heterostructure architecture and by the type II band alignment that can be obtained between CuO and ZnO, analysing the photodetecting properties of single CuO–ZnO core shell nanowires could lead to the fabrication of photodetectors with enhanced performances suitable in a wide range of applications.

Results

Conclusion