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

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 k Omega). 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.