Anisotropic photoresponse of two-dimensional layered α-In2Se3(2H) ferroelectric

The mechanical stripping method prepared the 2H-phase alpha-In2Se3 (alpha-In2Se3(2H)) nanosheets. The structure and ferroelectric properties of the nanosheets were characterized by X-ray diffraction (XRD), Raman spectroscopy, spherical aberration electron microscopy, and piezoelectric force microscopy. The nanosheets were identified as alpha-In(2)S(e)3( 2H) ferroelectric materials with a special structure. Further, a planar four-terminal device based on alpha-In2Se3 (2H) ferroelectricity was successfully constructed on the SiO2/Si substrate, and its photoresponse in all directions was investigated in detail. The results show that alpha-In2Se3(2H) with intrinsic structure has no photoresponse in both mutually perpendicular directions. After applying voltages at each end of the device, the alpha-In2Se3(2H) device shows obvious photoresponse in the mutually perpendicular directions. In particular, after utilizing a point voltage close to the direction of the easy polarization axis, the alpha-In2Se3(2H) device shows an anisotropic photoresponse.