Photoluminescence and optical response of ZnO films deposited on silicon and glass substrates

Abstract

ZnO films are synthesized by RF magnetron sputtering on silicon and glass substrates. Dry plasma is used to etch silicon at 5 min as well as 30 min for the purpose of surface modifications before depositing the films. ZnO films are compared with non etched substrate ones. Surface morphology characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Photoluminescence (PL) of ZnO films increased with increasing etching substrate time. The Photoresponse using Deuterium lamp, Ar laser and He-Cd laser was increased for ZnO films deposited on etched silicon substrate from 0 min to 30 min. No significant change was observed for optical band gap of ZnO films deposited on glass substrate. Films deposited on non etched Si (100) and glass substrates exhibit (002) preferred orientation, but the films with etching time for 5 and 30 min to silicon substrates become polycrystalline with accompanied (100) and (101) orientations as analyzed using x-ray diffraction (XRD). Electrical resistivity increases from 31 × 10−4 Ohm.cm to 218 × 10−4 Ohm.cm with increasing etching time of Si substrate.