Effective heat conservation in a sandwich-structured microbolometer using mesoporous TiO₂ layers

The heat loss of the a-Si:H resistor layer in a microbolometer might be reduced by using ordered mesoporous TiO₂ thin films as thermal insulation layers. Infrared absorption of mesoporous TiO₂ thin films in the 833-1250 cm^-1 wave number region was measured using a Fourier transform infrared spectrometer. Also, the infrared absorption rates of upper and lower mesoporous TiO₂ films inserted into the microbolometer were calculated to be above 84% in the 8-12 μm wavelength region. The CFD-ACE thermal simulation program was used to evaluate the thermal isolation effectiveness of mesoporous TiO₂ films on the a-Si:H layer; the inclusion of this film on the a-Si:H layer improved heat conservation. A mesoporous TiO₂ thin film effectively reduced the thermal loss from a-Si:H resistor surface and drastically increased the temperature of the resistor film.