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

This study introduces a VO 2 (B)/V 2 O 5 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 V 2 O 5 into the VO 2 (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 VO 2 (B) and insulating V 2 O 5 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 VO 2 (B)/V 2 O 5 nanocomposite as a robust and reliable material for LWIR detection in outdoor applications. • VO 2 (B)/V 2 O 5 heterointerface promotes interfacial charge separation under long-wave infrared (LWIR) illumination. • Charge separation enhances electron density, improving temperature coefficient of resistance (TCR) at 125 °C. • Larger hetero-interfacial area of VO 2 (B)/V 2 O 5 nanocomposite induces higher TCR. • VO 2 (B)/V 2 O 5 microbolometers exhibit high responsivity and detectivity at 125 °C.