High-performance thermal sensitive VO2(B) thin films prepared by sputtering with TiO2(A) buffer layer and first-principles calculations study

Abstract

VO₂(B) is a candidate material for thermal sensors in uncooled infrared detectors; however, it suffers from low temperature coefficient of resistance (TCR) values and unfavorable square resistances. Here, we present an effective strategy to modify the electronic properties of VO₂(B) by inducing elastic strain with an anatase TiO₂(A) buffer layer. The combined experimental and first-principles computational study on TiO₂(A)-induced VO₂(B) thin films deposited by magnetron sputtering enables us to achieve high TCRs (−3.48% K⁻¹) and favorable square resistances (18.97 kΩ). The underlying microscopic mechanism for the improvement in performance was studied, and the results indicate that the tensile strain contributes to a reduction in overlapping of V-3d orbitals and an increase in carrier concentrations along the c-axis in VO₂(B), both of which result in an increase in the electrical conductivity and TCR values. These findings promote the design and fabrication of high-performance VO₂(B) thin films by scaling the lattice strain along the c-axis with suitable buffer layers or substrates, and the simplicity of this method and the superior electrical properties of the films may enable its wide application in uncooled infrared detectors.