Augmented near-room-temperature power factor of homogenously grown thermoelectric ZnO films
Zhifang Zhou, Yunpeng Zheng, Yueyang Yang, Chang Liu, Bin Wei, Wenyu Zhang, Jinle Lan, Ce‐Wen Nan, Yuanhua Lin
Abstract
Future applications in power generation for wearable and portable electronics or active cooling for chips will benefit from near-room-temperature thermoelectric performance enhancement. Ga-doped ZnO (GZO) thin films are potential thermoelectric materials as they have the advantages of high cost-effectiveness, low toxicity, excellent stability, and high optical transparency. Inserting a ZnO buffer layer between the sapphire substrate and GZO thin films could contribute to optimizing carrier mobility and further improving electrical transport properties. However, thermoelectric performance at near-room-temperature ranges still needs to be promoted for practical applications. In this present study, ZnO single-crystal slices were directly selected as substrates for homogenously growing GZO thin films to further modify the substrate–film interface. The high Hall mobility of 47 cm2 V−1 s−1 and weighted mobility of 75 cm2 V−1 s−1 could be realized, resulting in better electrical transport performance. Consequently, the homogenously grown GZO thin films possessed competitively prominent power factor values of 333 μW m−1 K−2 at 300 K and 391 μW m−1 K−2 at 373 K. This work offers an effective avenue for optimizing the thermoelectric properties of oxide-based thin films via homogenous growth.