MEMS-Based Thermoelectric–Photoelectric Integrated Power Generator

Abstract

This letter presents a novel MEMS-based thermoelectric- photoelectric power generator, which integrates a micro-scale thermoelectric generator (μ-TEG) and a solar cell on a single silicon chip by MEMS technology for the first time. To optimize the heat flux path of μ-TEG, one side of the thermocouple square array is on the interdigitated electrode of the solar cell and the other side is on the thick oxide passivation layer to realize thermal isolation. Moreover, the hot side and the cold side are insulated by a thick polyimide thermal insulating layer above the thermopile, and a series of square holes is created to enhance the thermal coupling between the thermopile and surrounding environment. Several common measures, like the backsurface field and oxide passivation layer with limited contact openings, are adopted for the design of the solar cell. All the measuring electrodes are on the same side of the device for the convenience of bonding wire and package. When a sputtered Al membrane covers the front side of the device, the maximum output voltage factor and the power factor of the μ-TEG are 0.149 V·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and 3.03 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> μW·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> · K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , respectively. When the front and back sides of device receive light, the measured photoelectric conversion efficiencies are 4.45% and 0.682%, respectively.