Vanadium substitution: a simple and efficient way to improve UV sensing in ZnO

TL;DR

This paper demonstrates that vanadium doping significantly enhances UV sensing in ZnO by introducing defect states that facilitate electron trapping and de-trapping, leading to improved sensitivity.

Contribution

The study provides a simple doping method with vanadium to improve ZnO UV sensors and offers an analytic explanation of the underlying mechanism.

Findings

Vanadium doping increases UV sensitivity of ZnO.

Defect states V4+ and V5+ are key to the sensing mechanism.

Enhanced electron trapping/de-trapping improves sensor response.

Abstract

UV sensing in pure ZnO is due to oxygen adsorption/desorption process from ZnO surface. Vanadium doping improves UV sensitivity of ZnO. Enhancement in UV sensitivity in doped ZnO is attributed to trapping and de-trapping of electrons at V4+ & V5+-related defect states. An extra electron in the V4+ state is excited under UV illumination while in absence of the same a trapping happens at the V5+ state. An insight to the mechanism is obtained by an analytic study of the response phenomenon.