The Influence of Y Contribution on Crystallographic, Topographic and Optical Properties of ZnO: A Heterojunction Diode Application

Abstract

Pure and yttrium (Y) doped ZnO samples were fabricated on micro slide glasses and p-Si wafers for device application via a simple and cheap sol-gel route using a spin coater. The characterization results of XRD, SEM and UV/VIS spectrophotometer revealed the films to have nano-sized ZnO hexagonal wurtzite structures with (002) preferential orientation and optical band gap values depending on Y doping ratio. The optical band of 3.285 eV for pure ZnO initially increased to 3.305 eV, 3.332 eV and 3.341 eV for 1 at.%, 2 at.% and 3 at.% Y incorporated ZnO films and then decreased to 3.271 eV and 3.258 eV for 5 at.% and 7 at.% Y contents. The electrical features of Al/ZnO:Y/p-Si/Al heterojunction structures were tested by I-V measurements. The heterojunction structures showed a rectifying behavior under dark condition. The Phi(b), and n values for the devices were identified by using I-V measurements. It was observed that the rectification ratio value of 3 x 10(4) calculated at +3.0 V for Al/ZnO:Y/p-Si (5 at.% Y doped ZnO) heterojunction structure was higher than most of n-ZnO/p-Si heterojunction devices reported in the literature. (C) 2015 Elsevier Ltd. All rights reserved.