Optimizing the thermoelectric properties of flexible Bi0.5Sb1.5Te3 thin films via modulating magnetron sputtering power

Abstract

High-performance flexible Bi2Te3-based thin films carry significant promise for future portable and wearable thermoelectric devices. In this study, a series of Bi[Formula: see text]Sb[Formula: see text]Te3 thin films were deposited on polyimide substrates under different RF magnetron sputtering powers from 60 W to 140 W. The crystallinity, (00[Formula: see text]) preferential orientation and atomic composition can be effectively modulated by varying the sputtering power. Benefiting from the synchronous enhancements of the electrical conductivity (mostly due to the enhanced carrier mobility) and Seebeck coefficient, the film deposited under the sputtering power 100 W presents the best PF of 12.86 [Formula: see text]W cm[Formula: see text] K[Formula: see text] at 360 K and the highest average PF of 11.25 [Formula: see text]W cm[Formula: see text] K[Formula: see text] in the temperature range of 300–560 K, which are much better than those of the films deposited under other sputtering powers.