Modeling of the Photoelectric–Thermoelectric Integrated Micropower Generator

Abstract

Modeling of the photoelectric and thermoelectric integrated micropower generator is proposed in this article. This generator consists of a photoelectric generator and a microthermoelectric generator that can harvest optical and thermal energy at the same time. Photoelectric generator in this design is composed of several parallel p-n junctions on silicon substrate with Poly-Si electrodes above to receive light from both the top and the bottom sides of the chip. In order to take the advantage of CMOS process and integrate with the photoelectric generator, the microthermoelectric generator is designed to be hybrid and composed of series-wound thermocouples. The proposed model is based on the photovoltaic effect and the Seebeck effect. According to the results of the experiments, when light is received from the top side of the chip, the efficiency of the photoelectric generator is 4.11% and it is 0.5% when the bottom side is chosen to receive light. Geometry of the thermocouples dominates the performance of the microthermoelectric generator in this design. When the length and the width of the thermal legs are 75 and 20 μm, respectively, the microthermoelectric generator has the experimental output voltage factor of 0.316 Vcm <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> . The measured maximum output power factor of the microthermoelectric generator is 6.34×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> μWcm <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> .