High-Quality\nSnSe Thin Films for Self-Powered Devices\nand Multilevel Information Encryption

As\nsemiconductor technology advances toward miniaturization and\nportability, thin films with excellent thermoelectric performance\nhave garnered increasing attention, particularly for applications\nin self-powered devices and temperature-responsive sensors. The high\nSeebeck coefficient of SnSe thin films makes them promising for temperature\nsensing, but their poor electrical conductivity limits their potential\nas thermoelectric generators. In this work, high-quality <i>a</i>-axis oriented SnSe thin films were deposited on quartz substrates\nby using magnetron sputtering. The substrate temperature was optimized\nto improve the crystallinity of the SnSe thin film, resulting in larger\ngrain sizes, which subsequently contributes to the improved carrier\nmobility. The Seebeck coefficient is enhanced while optimizing the\nelectrical conductivity, enabling the SnSe thin film to achieve both\nexcellent sensing and power generation performance. The SnSe film\ndeposited at 673 K exhibits a high power factor of approximately 346\nμW m<sup>–1</sup> K<sup>–2</sup> at 620 K. A temperature-responsive\nsensing array was developed for multilevel information encryption,\nshowing significant potential for applications in password encryption.\nThe maximum output power density of the optimized thermoelectric generator\nwith six SnSe legs is about 9 W m<sup>–2</sup> at a temperature\ndifference of 50 K.