SiGe nanowire arrays based thermoelectric microgenerator

• Published in: Nano energy Vol. 57; pp. 492 - 499
• Main Authors: Donmez Noyan, Inci, Gadea, Gerard, Salleras, Marc, Pacios, Merce, Calaza, Carlos, Stranz, Andrej, Dolcet, Marc, Morata, Alex, Tarancon, Albert, Fonseca, Luis
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2019
• Subjects: Energy harvesting; MEMS; SiGe nanowires; Thermoelectric micro/nanogenerator; VLS-CVD; MEMS; Thermoelectric micro/nanogenerator; Energy harvesting; SiGe nanowires; VLS-CVD
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.12.050

Thermoelectric micro/nanogenerators (µTEGs) are potential candidates as energy harvesters to power IoT sensors. This study reports on a thermoelectric micro/nanogenerator with a planar architecture built by silicon micromachining technologies that uses silicon-germanium (SiGe) nanowire (NW) arrays as thermoelectric material. The growth of bottom-up NW arrays by means of Chemical Vapour Deposition - Vapour Liquid Solid growth (CVD-VLS) and their monolithic integration into prefabricated microplatforms are presented. It is shown that SiGe NWs based µTEGs can harvest 7.1 μW/cm2 without any additional heat exchanger, when there is a waste heat source available at a temperature of 200 °C. Since the required power density for many sensing applications is in the range of 10–100 μW/cm2 the results obtained in this work are close to meet expectations.
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•Energy harvesting is in high demand for powering IoT devices.•Proposed device is compatible with Si microtechnologies and enabling mass production.•Proposed device smartly combines top-down and bottom-up technologies.•SiGe nanowires are integrated into thermal generator device for the first time.•Low k of SiGe enabled good thermal isolation and high power densities.