Nithin Pulumati1,2,Aditya S Dutt1,2,Kangfa Deng1,Kornelius Nielsch1,2,Heiko Reith1
Leibniz Institute for Solid State and Materials Research1,TU Dresden2
Nithin Pulumati1,2,Aditya S Dutt1,2,Kangfa Deng1,Kornelius Nielsch1,2,Heiko Reith1
Leibniz Institute for Solid State and Materials Research1,TU Dresden2
Generation of electricity without leaving a vast carbon footprint represents one of the critical challenges of the 21<sup>st</sup> century. Around 60% of energy is dissipated in the form of heat while burning fossil fuels. Thermoelectric devices have drawn a wide interest because of its potential to convert waste heat into clean electricity and vice-versa. For applications like in biomedical and Internet of things, µTEDs need to have a robust packaging so that the devices can be brought in direct thermal contact with the target heat sink and source. The packaging technology developed for macroscopic modules needs improvement as it cannot be applied to µTEDs due to a large thermal resistance between the capping material and the device which deteriorates its performance. Here, we develop µTEDs using optimized geometry and contact resistance combined with a novel packaging technique that is fully compatible with on-chip integration.<br/>We developed a process for the fabrication of µTEDs with vertically free-standing leg pairs without a top plate. The fabricated µTEDs were embedded in a photoresist for using the device in applications.<br/>The fabrication of the µTED is based on the combination of photolithographic patterning process with electrochemical deposition of Bi<sub>2</sub>(Te<sub>x</sub>Se<sub>1-x</sub>)<sub>3 </sub>and Te as n-type and p-type thermoelectric materials respectively. Using the optimized geometry and contact resistance, the maximum net cooling temperature and the cycling reliability were enhanced. The geometrically optimized µTED with low contact resistance showed a maximum cooling of around 10.8K at an applied electrical current of 235mA, a rapid response time of 700µs and survived over 100 million cooling cycles in our reliability studies [1]. The fabricated µTED can be used to scavenge waste heat to provide solid-state electricity for powering electronics and have potential applications in wearable electronics, and wireless sensors. These embedded, optimized, stable and easily scalable µTEDs open new avenues for widespread applications in biomedical applications, powering internet-of-things devices, and local heat management.<br/><b>Reference</b><br/>[1] Dutt, et al., Adv. Electron. Mater. (2022): 2101042.