Characterization and Optoelectronic Effects of Iridium Doped ZnO Thin Films for Heterojunction Applications

Abstract

In this investigation, the sol-gel spin coating technique was utilized to fabricate ZnO and ZnO films doped with Iridium (Ir) onto p-Si substrates. The objective was to analyze their optical and morphological characteristics and assess their potential for heterojunction applications. Morphological inspection and optical evaluation were carried out by Atomic Force Microscopy (AFM) and Ultraviolet-visible (UV-VIS) studies, respectively. With the incorporation of Ir, the optical band gap of ZnO films reduced from 3.21 eV to 3.08 eV. Analysis of AFM images revealed that Ir substitution led to a reduction in the roughness of the surface of the fabricated films. The optoelectrical features of the heterojunction structures were examined under varying illumination levels and in dark conditions. Upon evaluating the optoelectrical characteristics of the produced diodes, it was observed that the ideality factor (n) and the barrier height declined, while series resistance (Rs) increased with the introduction of Ir. These findings emphasize that the inclusion of Ir into the ZnO structure has a discernible impact on optical parameters.