Thermoelectric devices enable direct conversion between thermal and electrical energy. Recent studies have indicated that the thin film/substrate heterostructure is effective in achieving high thermoelectric performance via decoupling the Seebeck coefficient and electrical conductivity otherwise adversely inter-dependent in homogenous bulk materials. However, the mechanism underlying the thin film/substrate heterostructure thermoelectricity remains unclear. In addition, the power output of the thin film/substrate heterostructure is limited to the nanowatt scale to date, falling short of the practical application requirement. Here, we fabricated the CrN/SrTiO_3−x heterostructures with high thermoelectric output power and outstanding thermal stability. By varying the CrN film thickness and the reduction degree of SrTiO_3−x substrate, the optimized power output and the power density have respectively reached 276 μW and 108 mW/cm² for the 30 nm CrN film on a highly reduced surface of SrTiO_3−x under a temperature difference of 300 K. The performance enhancement is attributed to the CrN/SrTiO_3−x heterointerface, corroborated by the band bending as revealed by the scanning Kelvin probe microscopy. These results will stimulate further research efforts towards interface thermoelectrics.

热电设备可实现热能和电能之间的直接转换。最近的研究表明，薄膜/衬底异质结构可通过将塞贝克系数和电导率解耦来有效地实现高热电性能，否则它们在均质块状材料中会相互依存。但是，薄膜/衬底异质结构热电的机理尚不清楚。另外，迄今为止，薄膜/衬底异质结构的功率输出被限制为纳瓦级，达不到实际应用要求。在这里，我们制作了CrN / SrTiO _{3- x}具有高热电输出功率和出色的热稳定性的异质结构。通过改变CrN膜的厚度和SrTiO _{3- x}衬底的还原度，对于SrTiO ₃高度还原的表面上的30 nm CrN膜，优化的功率输出和功率密度分别达到276μW和108 mW / cm ²。_{− x}在300 K的温差下。性能增强归因于CrN / SrTiO _{3- x}异质界面，由扫描开尔文探针显微镜显示的能带弯曲证实了这一点。这些结果将刺激对界面热电学的进一步研究。