Chalcogenide Glass Bolometers

Abstract

The chalcogenide glass Tl2SeAs2Te3 has been evaluated as a thermistor bolometer material for room temperature operation. Thin film bolometers were fabricated on mica, glass, and sapphire substrates by both hot-pressing and rf sputtering techniques. Best results were achieved with 10-μ thick Tl2SeAs2Te3 elements on thin mica substrates. Using a 500 K blackbody at a 10-Hz chopping frequency, a 2.5 × 10−3-cm2 device yielded an NEP of 2.3 × 10−9 W Hz−1/2, and a 10−4-cm2 device achieved an NEP of 7.7 × 10−10 W Hz−1/2. The ac performance of these devices is limited by their inherently long response times (τ ≅ 1 sec).