Enhancement in UV emission and band gap by Fe doping in ZnO thin films

摘要

Enhancement of the optical band gap of ZnO from 3.14 to 3.29 eV has been obtained using Fe dopant. Undoped and doped ZnO films are deposited by sol?gel spin coating. XRD patterns indicate polycrystalline nature and hexagonal wurtzite structure of Zn_(1–x) Fe_xO films. EDX analysis confirms the presence of iron dopant. The photoluminescence spectra show an ultraviolet emission peak at 398 nm (NBE emission) and defect emission peak at 485 nm. Intensity of the NBE emission is much higher for the doped samples with its ratio to defect emission intensity highest for 2 at. %doping. The NBE emission shifts to higher energy with increasing dopant concentration in a manner similar to that exhibited by the band gap. Surface morphology has been studied using FESEM.