Metal-to-insulator transition in anatase TiO2 thin films induced by growth rate modulation

TL;DR

This study shows how adjusting growth rate during pulsed laser deposition can control carrier density and induce a metal-insulator transition in anatase TiO2 thin films, with implications for electronic properties.

Contribution

It introduces a method to modulate carrier density in TiO2 thin films via growth rate control, supported by a quantitative model linking growth kinetics to electronic properties.

Findings

Carrier density varies by nearly two orders of magnitude with growth rate.

Resistivity and photoluminescence intensity depend on oxygen vacancy concentration.

A quantitative model explains the relationship between growth kinetics and carrier density.

Abstract

We demonstrate control of the carrier density of single phase anatase TiO2 thin films by nearly two orders of magnitude by modulating the growth kinetics during pulsed laser deposition, under fixed thermodynamic conditions. The resistivity and the intensity of the photoluminescence spectra of these TiO2 samples, both of which correlate with the number of oxygen vacancies, are shown to depend strongly on the growth rate. A quantitative model is used to explain the carrier density changes.