High-performance metal–semiconductor–metal UV photodetector based on spray deposited ZnO thin films

Abstract

Zinc oxide (ZnO) based metal–semiconductor–metal (MSM) ultraviolet photodetectors at different substrate temperatures were fabricated on glass substrates by economical chemical spray pyrolysis technique and its UV photoresponsivity was measured at room temperature. The samples were characterized with respect to their structural, morphological, and optical properties using various methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy, transmittance, reflectance etc. The synthesized ZnO thin films were c-axis oriented with hexagonal crystal structure as confirmed from XRD. All deposited films were specular and show high transmittance (∼85%) in visible region with steep fall off at 375nm. The photoconductive MSM UV photodetector showed relatively high photocurrent (1.3mA) and fast switching. ZnO thin films exhibited relatively high photoresponsivity (788A/W) with cut of wavelength ∼375nm signifying their application as UV detector.