Modeling and performance of vanadium-oxide transition edge microbolometers

The performance of a VO2 thin-film microbolometer has been investigated. The device is operated within 35 degreesC<60 degreesC, in the hysteretic metal-insulator transition region. An algebraic hysteresis model has been used to model the resistance-temperature characteristic of the sensor. It accurately describes the resistance versus temperature characteristics of the material. Employing this model, and in conjunction with established bolometer theory, the responsivity of a VO2 film is calculated and compared with experimental data. Superior performance of the device is achievable under conditions of single pulse incident radiation where the operating point remains on the major hysteresis loop. This results in a pronounced responsivity peak within the center of the metal-insulator transition. Continuous periodic excitation, in contrast, leads to a steadily decreasing and much lower sensitivity at higher temperature, due to the formation of minor hysteresis loops and the loop accommodation process. (C) 2004 American Institute of Physics.