Optimization of Thermoelectric Performance of Ag₂Te Films via a Co-Sputtering Method

Providing self-powered energy for wearable electronic devices is currently an important research direction in the field of thermoelectric (TE) thin films. In this study, a simple dual-source magnetron sputtering method was used to prepare Ag₂Te thin films, which exhibit good TE properties at room temperature, and the growth temperature and subsequent annealing process were optimized to obtain high-quality films. The experimental results show that films grown at a substrate temperature of 280 °C exhibit a high power factor (PF) of ~3.95 μW/cm·K² at room temperature, which is further improved to 4.79 μW/cm·K² after optimal annealing treatment, and a highest PF of ~7.85 μW/cm·K² was observed at 200 °C. Appropriate annealing temperature effectively increases the carrier mobility of the Ag₂Te films and adjusts the Ag/Te ratio to make the composition closer to the stoichiometric ratio, thus promoting the enhancement of electrical transport properties. A TE device with five legs was assembled using as-fabricated Ag₂Te thin films. With a temperature difference of 40 K, the device was able to generate an output voltage of approximately 14.43 mV and a corresponding power of about 50.52 nW. This work not only prepared a high-performance Ag₂Te film but also demonstrated its application prospects in the field of self-powered electronic devices.