A study of hydrothermally grown ZnO nanorod-based metal-semiconductor-metal UV detectors on glass substrates

Shaivalini Singh,Chinnamuthan Periasamy,Si-Hyun Park,Yogesh Kumar,Hemant Kumar,Satyabrata Jit,Parthasarathi Chakrabarti,Sumit Vyas

doi:10.1177/1847980417702144

Abstract

This study reports hydrothermally grown zinc oxide nanorod-based metal-semiconductor-metal ultraviolet detectors with palladium metal as the electrodes. The zinc oxide nanorods were deposited on glass substrates in two steps, seed layer deposition and growth of nanorods. The structural and optical properties of nanorods were examined using scanning electron microscopy and ultraviolet–vis spectroscopy, respectively. The scanning electron microscopy image showed that the growth of nanorods was uniform, and the ultraviolet–vis results indicate that the bandgap of zinc oxide nanorods was 3.23 eV. For metal-semiconductor-metal devices, interdigited metal electrodes with equal interelectrode spacing and a width of 0.3 mm were deposited above the zinc oxide nanorod thin films with a shadow mask using a thermal evaporation system. The current–voltage characteristics of the metal-semiconductor-metal detector were investigated and it showed a contrast ratio of approximately 2.10 and responsivity of approximately 0.199 A/W at 1.8 V. These results are expected to be beneficial to fabricating cheap and practical ultraviolet detection applications.

Highlights

Zinc oxide (ZnO) is a promising semiconductor material for ultraviolet (UV) and blue light detection-based applications such as optically pumped lasers,[1] photodetectors (PDs),[2,3] and light-emitting diodes.[4]
Several studies have been performed on UV PDs using ZnO NRs fabricated using the hydrothermal method as well as other growth techniques.[22,24,25,26]
Many research groups are working on ZnO MSM UV PDs, there are very few studies on hydrothermally grown NR-based MSM UV detectors

Summary

Introduction

Zinc oxide (ZnO) is a promising semiconductor material for ultraviolet (UV) and blue light detection-based applications such as optically pumped lasers,[1] photodetectors (PDs),[2,3] and light-emitting diodes.[4]. They used gold (Au) metal electrodes for their MSM devices and reported photosensitivity values of 97 mA/W at approximately 325-nm illumination and 44 mA/W at approximately 518-nm illumination at a bias of 5 V, for their MSM UV detectors.[16] Lee et al reported hydrothermally grown ZnO NR-based near-UV PDs with an MSM structure. Conventional photolithography was used for the fabrication of MSM structures, and titanium/Au was used as the metal electrodes.[24] many research groups are working on ZnO MSM UV PDs, there are very few studies on hydrothermally grown NR-based MSM UV detectors.

Results

Conclusion