Reduction of oxygen vacancy related defects in RF sputtered deposited ZnO films by impurity (Phosphorus) incorporation

Abstract

ZnO is a fascinating wide gap (3.37 eV) semiconductor due to its tunable optical and electrical properties, which can be utilized for several nanodevices such as nanogenerators, photodetectors, sensors, lasers, and TFTs. In this study, we have investigated the effect of the incorporation of dopants on the native defects and corresponding optical properties of ZnO. We have prepared three samples for the current study and such samples are named samples Z-0, Z-1, and Z-2 for undoped ZnO film, undoped ZnO film annealed at 800°C, and phosphorus doped ZnO film by using spin-on dopant method at an elevated temperature of 800°C, respectively. The XRD results show a dominant peak along the (002) plane for all samples. The Room-temperature photoluminescence spectra reveal that the broad peak around 542 nm for sample Z-0 gradually shifts towards the UV region for samples Z-1 and Z-2 and appears around 509 nm and 413 nm, respectively. Significantly, such blue emission is associated with the transitions from oxygen vacancies to valence band or zinc interstitial to valance band. Also, relatively huge reductions in oxygen vacancies are observed in phosphorus doped ZnO films as compared with undoped and undoped-anneal films. Further, we have verified such reductions in oxygen vacancies with XPS O-1s spectra-related peaks (~531-532 eV) with high-temperature annealing and phosphorus doping. Therefore, such a type of oxygen vacancy reduction in ZnO films by cost-effective SOD doping technique is highly essential for developing several ZnObased functional devices. © 2022 SPIE.