Brookite-phase vanadium (IV) oxide formation for semiconductor-to-metal transition free bolometric membrane via atomic layer deposition technique

In this study, we investigated the formation of brookite-phase vanadium (IV) oxide (VO2) thin films, focusing on their potential application in bolometric membranes without semiconductor-to-metal transition (SMT) behavior. Using atomic layer deposition (ALD), we controlled the crystallization of VO2 thin films by varying the deposition temperature from 140 to 250 °C. X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) analyses revealed that films deposited at 250 °C predominantly crystallized into the brookite phase, while lower temperatures led to monoclinic-phase VO2, which undergoes SMT behavior. Electrical measurements showed that films deposited at 250 °C demonstrated superior bolometric properties with a stable temperature coefficient of resistance (TCR) and minimal 1/f noise, even after thermal stress testing. In contrast, films with higher monoclinic-phase content exhibited significant SMT behavior and degraded performance. These results suggest that brookite-phase VO2 films, free from SMT behavior, are promising candidates for high-performance microbolometer applications.