Angle-Engineered Bi_0.94La_0.06CuSeO Thin Films for High-Performance Transverse Thermoelectric Devices

BiCuSeO has emerged as a highly promising material for transverse thermoelectric (TTE) applications, with its performance significantly enhanced through La doping. In this study, we investigate the effect of inclination angle on the TTE performance of inclined Bi_0.94La_0.06CuSeO thin films fabricated using the pulsed laser deposition technique. A huge output voltage of 31.4 V was achieved in the 10° inclined Bi_0.94La_0.06CuSeO film under 308 nm ultraviolet pulsed laser irradiation. Furthermore, the films also exhibited significant response with excellent linearity when exposed to continuous-wave lasers across a broad spectral range (360 nm to 10,600 nm) and a point-like heat source. Notably, the voltage is directly proportional to sin2θ, where θ is the inclination angle. These findings not only provide a clear optimization strategy for TTE performance through inclination angle engineering but also highlight the material's great potential for developing high-performance optical and thermal sensing TTE devices.