Synthesis of Ga-Doped ZnO Nanorods by Hydrothermal Method and Their Application to Ultraviolet Photodetector

Sheng-Joue Young,Chia-Lin Chiou,Liang-Wen Ji,Yi-Hsing Liu

doi:10.3390/inventions1010003

Sheng-Joue Young, Chia-Lin Chiou + Show 2 more

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https://doi.org/10.3390/inventions1010003

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Abstract

In this study, high-density single crystalline Ga-doped ZnO (GZO) nanorods were grown on glass substrate by the hydrothermal method. The structural and optoelectronic properties of Ga-doped ZnO nanorods were studied. The microstructure of the GZO was studied by scanning electrical microscope (SEM). The structural characteristics of the GZO were measured by X-ray diffraction (XRD). It was found that the peaks related to the wurtzite structure ZnO (100), (002), and (101) diffraction peaks. The (002) peak indicates that the nanorods were preferentially oriented in the c-axis direction. The existence of Ga was examined by energy diffraction spectra (EDS), indicating the Ga atom entered into the ZnO lattice. The optical properties of the GZO were measured by photoluminescence spectra. It was found that all GZO nanorod arrays showed two different emissions, including UV (ultraviolet) and green emissions. GZO nanorod metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PD) were also fabricated. The photo-current and dark-current constant ratio of the fabricated PD was approximately 15.2 when biased at 1 V.

Highlights

ZnO has several favorable properties, such as a wide bandgap (3.37 eV) and a large exciton-binding energy (60 meV)
ZnO nanorods are doped with various elements to alter their structural, electrical, and optical characteristics
Ga, and In elements are used as dopants in the fabrication of n-type ZnO nanorods

Summary

Introduction

ZnO has several favorable properties, such as a wide bandgap (3.37 eV) and a large exciton-binding energy (60 meV). Forms of ZnO with wurtzite structures have various morphologies such as nanowires, nanorods, nanotubes, and nanobelts [1,2,3,4,5]. ZnO nanorods are doped with various elements to alter their structural, electrical, and optical characteristics. Ga, and In (group III) elements are used as dopants in the fabrication of n-type ZnO nanorods. Ga is an excellent dopant with high conductivity and low reactivity. As the covalent bond length of Ga–O, 1.92 Å is very close to that of Zn–O, which is

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