SnSe has recently drawn extensive attention as a promising thermoelectric (TE) material since the discovery of record high figure of merit (zT, ∼2.6) in the monocrystalline bulk. However, thin films with remarkable TE performance are highly desired for microscale devices used as semiconductor coolers or power wireless sensors. Studies on the preparation and the TE properties of SnSe epitaxial thin films are scarce to date. Herein, a-axis-oriented SnSe epitaxial films were successfully prepared via the pulsed laser deposition technology. The thin films exhibited a relatively high power factor (PF) of ∼472 μW⋅m⁻¹ K⁻² at 600 K along the in-plane direction perpendicular to the a-axis after the optimization of Sn vacancy concentration. The out-of-plane thermal conductivities of the thin films decreased by 33% compared with that of the single-crystalline bulk. The in-plane thermal conductivities were conservatively estimated using the proportion between a and b axes in the single-crystalline bulk. An ultrahigh estimated-zT value (approximately 1.2 at 600 K) was achieved along the in-plane direction of SnSe thin films. The superior thermal stability of the high-quality samples was also investigated via an ex situ annealing process, and the corresponding PF and estimated-zT remained at high values (445 μW⋅m⁻¹ K⁻² and 1.1, respectively). The surprisingly high TE properties and the rational preparation solution in this study will greatly contribute to the promotion of the prospective practical application of SnSe thin films.

自从发现单晶体中创纪录的高品质因数（zT，〜2.6）以来，SnSe作为一种有前途的热电（TE）材料已引起了广泛关注。但是，对于用作半导体冷却器或功率无线传感器的微型器件，人们强烈希望具有出色的TE性能的薄膜。到目前为止，对SnSe外延薄膜的制备和TE性能的研究还很少。本文中，通过脉冲激光沉积技术成功制备了轴取向的SnSe外延膜。薄膜 在垂直于薄膜的面内方向上在600 K处表现出相对较高的功率因数（PF），约为472μW·m ^-1  K ^-2。优化锡空位浓度后的a轴。与单晶块相比，薄膜的面外导热率降低了33％。使用的比例的面内的热导率被保守地估计一个和b在单晶块状轴。超高estimated- zT值的值（大约1.2，在600 K）沿位SnSe薄膜的面内方向来实现的。还通过异位退火工艺研究了高质量样品的优异热稳定性，并且相应的PF和估计的zT保持在较高值（445μW·m ^-1  K^-2和1.1）。这项研究中出乎意料的高TE性能和合理的制备解决方案将极大地促进SnSe薄膜的预期实际应用。