Enhanced light-induced transverse thermoelectric effect in c-axis inclined Ba-doped BiCuSeO thin films

Abstract A significant enhancement of the light-induced transverse thermoelectric (LITT) effect is obtained in c-axis inclined BiCuSeO films through Ba doping. Upon the irradiation of a 308nm pulsed laser, the LITT voltage signal in Ba-doped film shows higher sensitivity R and faster response time. The maximum sensitivity R of 5.9 V/mJ is obtained in Bi0.94Ba0.06CuSeO film, which is 4.9 times that of the intrinsic film (1.2 V/mJ). The improvement of LITT performance can be attributed to the increased Seebeck coefficient anisotropy and the decreased film resistivity due to the increase in hole carrier concentration of the Ba-doped films. For the case of irradiation from a continuous laser with wavelength of 532, 1064 and 1550 nm, respectively, obvious LITT voltage signals can be detected in film of Bi0.94Ba0.06CuSeO, and the induced voltage amplitude Vp increases with increasing power or reducing wavelength λ of the irradiated laser. This work demonstrates the potential application of Ba-doped BiCuSeO film in self-powered photodetectors, especially in high sensitivity and fast response UV detectors.