Heterointerface photo-electron effect in VO2(B)/V2O5 nanocomposite under long-wave infrared illumination for high-temperature microbolometers

Abstract

This study introduces a VO2(B)/V2O5 nanocomposite thin film, fabricated via low-temperature sputtering (< 300 °C), as a high-performance thermistor material at high temperatures up to 125 °C for long-wave infrared (LWIR) microbolometers. By incorporating V2O5 into the VO2(B) matrix and optimizing the heterointerface, the composite achieves a high temperature coefficient of resistance (TCR) of 2.19 (？/K) at room temperature and 1.19 (？%/K) at 125 °C. The synergistic properties of conductive VO2(B) and insulating V2O5 enhance interfacial charge transfer, electron density, and thermal stability. Structural and compositional analyses confirm that oxygen vacancies and optimized band alignment play key roles in improving conductivity and photo-response. The microbolometers exhibit exceptional responsivity (2.3 kV/W) and fast response times (∼ 0.72 ms) at elevated temperature of 125 °C, highlighting the VO2(B)/V2O5 nanocomposite as a robust and reliable material for LWIR detection in outdoor applications.