Selective growth of ZnO nanorods on microgap electrodes and their applications in UV sensors

Qazi Humayun,Uda Hashim,Ahsanulhaq Qurashi,Muhammad Kashif

doi:10.1186/1556-276x-9-29

Abstract

Selective area growth of ZnO nanorods is accomplished on microgap electrodes (spacing of 6 μm) by using a facile wet chemical etching process. The growth of ZnO nanorods on a selected area of microgap electrode is carried out by hydrothermal synthesis forming nanorod bridge between two electrodes. This is an attractive, genuine, direct, and highly reproducible technique to grow nanowire/nanorod onto the electrodes on selected area. The ZnO nanorods were grown at 90°C on the pre-patterned electrode system without destroying the electrode surface structure interface and geometry. The ZnO nanorods were tested for their application in ultraviolet (UV) sensors. The photocurrent-to-dark (Iph/Id) ratio was 3.11. At an applied voltage of 5 V, the response and recovery time was 72 and 110 s, respectively, and the response reached 2 A/W. The deposited ZnO nanorods exhibited a UV photoresponse that is promising for future cost-effective and low-power electronic UV-sensing applications.

Highlights

Metal-oxide-semiconductor nanostructures have received considerable attention worldwide because of their excellent physical and chemical properties in the recent past [1]
We report the deposition of zinc oxide (ZnO) nanorods on a selective area of microgap electrodes through simple low-cost, highly reproducible hydrothermal technique, and their applications in UV sensors were investigated
The SEM showed the morphological features of the ZnO nanorods deposited on a selected area of microgap electrodes

Summary

Introduction

Metal-oxide-semiconductor nanostructures have received considerable attention worldwide because of their excellent physical and chemical properties in the recent past [1]. Zinc oxide (ZnO) nanostructures have attracted significant interest because of their large wide direct bandgap (Eg = 3.37 eV) [2] and high exciton binding energy (60 meV) [2,3,4]. The direct flow of electrons contributes to the maximum photocurrent generation because of the large interfacial surface area [9]. In contrast to GaN, ZnO has a maximum electron saturation velocity; photodetectors equipped with ZnO can perform at a maximum operation speed [10]. Different types of photosensors, such as p-n junction, metal–semiconductor-metal, and Schottky diodes, have been fabricated. Metal–semiconductor-metal photosensors are becoming popular because of their simple

Methods

Results

Conclusion