Work-Function-Dependent Interface Engineering and Charge Transport in M-NiO Schottky Diodes with M= Al, Ag, and Au Contacts

Abstract

Metal–semiconductor interface engineering provides an effective approach for tailoring charge transport and rectification in oxide-based electronic devices. In this work, the influence of metal work function on the electrical characteristics of NiO-based Schottky diodes deposited on glass substrates is systematically investigated using Al, Ag, and Au as contact metals. NiO thin films were deposited on glass under controlled conditions, followed by the fabrication of Al/NiO, Ag/NiO, and Au/NiO device structures using identical processing conditions. The current–voltage (I–V) characteristics were analyzed to evaluate the Schottky barrier height, ideality factor, series resistance, rectification ratio, and reverse leakage current. The three metal contacts exhibited distinct diode characteristics, demonstrating the important role of metal work function and interfacial energy alignment in governing carrier transport across the metal/NiO interface. The variation in barrier characteristics was further correlated with interface states, defect-assisted transport, and possible Fermi-level pinning effects. Among the investigated contacts, the Al, Ag, and Au interfaces provide a systematic low-, intermediate-, and high-work-function comparison, allowing the relationship between contact-metal selection and charge-transport behavior to be established. The findings demonstrate that appropriate engineering of the metal/NiO interface can effectively tune Schottky barrier formation, leakage current, and rectification performance. This study provides a simple strategy for optimizing NiO-based Schottky contacts for oxide electronic and optoelectronic applications.

Keywords: Semiconductor; Schottky barrier; optoelectronic applications