Thickness dependence of microstructure and thermoelectric performance in Ag2Se films

Abstract

With the increasing demand for energy autonomy in electronic systems, the research on thin-film-based energy harvesting devices has garnered significant attention. In this work, Ag2Se films with varying thicknesses on quartz glass substrates were fabricated using the magnetron sputtering technique and a straightforward selenization reaction. Charge transport and thermoelectric performance of these films were investigated in the low-temperature range of 300 K to 400 K. Considerable high room-temperature power factor (>2000 μW m-1 K-2) was achieved as the thickness of films exceeded 1000 nm, attributed to the favorable orientation and crystallization. A 5-leg thermoelectric prototype was assembled with 1600 nm-thickness Ag2Se film because of its highest power factor of 2530 μW m-1 K-2 at 300 K. Maximum output power density of 29.8 W m-2 and 87.7 W m-2 were obtained at the temperature difference of 30 K and 50 K respectively, surpassing the majority of the previous reports.