A Review on Microbolometer Materials: Preparation, Properties, and Device Applications

Microbolometers are infrared detectors whose resistance changes with temperature. The infrared radiation from objects located at various temperatures falls on top of a microbolometer surface, causing its temperature to increase, which in turn changes the bolometer’s resistance. While a-Si and vanadium oxide (VO x ) are the two most widely used microbolometer materials for commercial applications, several other new materials, such as doped-VO x , germanium-based alloys, niobium oxide, titanium oxide, carbon nanotubes, and graphene, have also shown potential. This review provides a thorough analysis of conventional and potential new materials used in the sensing layer of microbolometers. Furthermore, it covers the atomic compositions of each material, their deposition and synthesis processes, and their electro-optical and other properties relevant to microbolometer applications. This periodic analysis also provides in-depth descriptions of the figures of merit for microbolometers made from each of the materials used so far. These figures of merit include the temperature coefficient of resistance, responsivity, detectivity, and noise equivalent temperature difference (NETD), among others. The performance of microbolometers made of each of the materials is also compared.