Thermoelectric effect and devices on IVA and VA Xenes

Abstract Emerging Xenes, mostly group IVA and VA elemental two‐dimensional (2D) materials, have small and tunable band gaps between graphene and transition metal dichalcogenides, giving versatile electrical properties. While their microelectronic or optoelectronic properties are being extensively explored, there remains a lack of study on Xenes' uniquely advantageous thermoelectric performance. This review highlights state‐of‐the‐art experimental and theoretical progress in the thermoelectric effect and devices of IVA and VA Xenes. Vertically displaced, a.k.a. “buckled” or “puckered,” atomic arrays result in exotic and tunable electrical or thermal transport behaviors. Different from chemical doping strategies usually employed in bulk thermoelectric materials, 2D Xenes can be tuned by physical means, such as atomic layer control and quantum confinement effects. A precise and compatible platform for 2D thermoelectric effect and devices study is available via the engagement between micro/nanofabrication of 2D Xene transistors and thermal property measurement techniques. This review also reveals potential thermoelectric applications of Xenes and their compounds (Bi2Te3, Bi2Se3, etc.), such as accurate stretchable temperature sensors, fast terahertz photodetectors, and so on.