Optimization of Bi2Te3 thin films for microintegrated Peltier heat pumps

Abstract

Bismuth telluride films were deposited by coevaporation at various Te/Bi flux ratios to optimize their resistivity and their Seebeck coefficients for use in a thin film Peltier heat pump. Bismuth telluride films deposited at a flux ratio of Te/Bi=2.3 were found to possess optimal characteristics. Using these coatings, microintegrated Peltier heat pumps were fabricated on micromachined oxide bridges using standard semiconductor patterning and etching techniques. Chrome–gold and bismuth telluride metallizations were used to form the thermoelectric junctions. A maximum heat pumping rate of −30 μW was achieved by the device when operating in the cooling mode. A temperature reduction of 1.5 °C was attained, with an initial thermal response time in the cooling mode of 10 ms/°C.