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

摘要

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 308 nm 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 V-p increases with increasing power or reducing wavelength lambda 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.