Photoelectric and pyroelectric performance modulated by the in-plane ferroelectric polarization in multi-functional α-In2Se3-based transistor

As a typical two-dimensional van der Waals ferroelectric material, α-In2Se3 has great potential in the applications of optoelectronic devices, memories, sensors, detectors, and synapses. Although it has been proved that α-In2Se3 is with simultaneous intercorrelated in-plane and out-of-plane ferroelectric polarization, the degree-of-freedom of in-plane ferroelectric polarization in the α-In2Se3 and its influence on the other properties have always been neglected because of the difficulties in the characterization and application, comparing with the out-of-plane ferroelectric polarization. Specifically, it has not been revealed the influence mechanism how the in-plane ferroelectric polarization modifies the photodetection performance of the α-In2Se3-based transistor. In this report, the four-terminal transistors based on the multi-layered α-In2Se3 are prepared and used to investigate the in-plane ferroelectric polarization influenced photodetection performance. We have demonstrated that the in-plane ferroelectric polarization may reduce the optical response time of α-In2Se3-based transistors, and the pyroelectric performance induced by the in-plane ferroelectric polarization adds a feature to the α-In2Se3-based transistors. These results promote the four-terminal α-In2Se3-based transistor to be a multi-functional device, which can simultaneously detect the light and its induced temperature variation. Our work may offer an approach to understand the in-plane ferroelectric polarization-modulated multi-functional optoelectronics.