GaN based 2DHG thermoelectric characterization for u-TEGs

Abstract

Thermoelectric generators (TEGs) are critical in environments where alternative energy harvesting methods are necessary, such as space exploration. This thesis investigates using a two-dimensional hole gas (2DHG) as a p-type material within a Gallium Nitride (GaN) based TEG. This study focuses on determining the thermoelectric performance of the 2DHG by measuring the Seebeck coefficient, electrical conductivity, and power factor for extremely cold environments.

This work introduces a novel simulation method used to evaluate different structures to find the optimal hole densities for maximizing the power factor (PF) of the 2DHG. A structure was realized, and its thermoelectric properties were experimentally assessed. Key results, including a Seebeck coefficient of 100 − 200 μV /∆K, a sheet resistance of 70 − 120 kΩ , and a resulting Power Factor (PF) of 60 − 100 μW m−1K−2, are measured over an extremely low-temperature range of 50 - 300 Kelvin and discussed for future applications.

These results demonstrate that GaN-based TEGs can significantly broaden the temperature range and improve the performance of TEGs in extreme conditions. These findings pave the way for more efficient thermoelectric systems, with potential applications in aerospace, deep-space missions, and other challenging environments.