Wide-Spectrum Polarization-Sensitive Photodetector Based on Spontaneous GaTe/Ga-2(TexO1-x)(5 )Heterostructure

Low-dimensional semiconductor materials with in-plane anisotropy have attracted increasing atten-tion due to the novel physicochemical properties induced by the special lattice structure. Among III-group metal chalcogenides, GaS, GaSe, and In2Se3 have been reported impressive performances in microelectronics, optoelec-tronics, and ferroelectronics. Therefore, the investigation on the III-group chalcogenides and their heterostruc-tures is important for diverse applications with promis-ing functionalities. Gallium telluride (GaTe), as a typical III-group chalcogenide 2-D semiconductor with in-plane anisotropy, can be oxidized in atmosphere, thus form-ing a spontaneous van der Waals heterostructure con-sisting of GaTe and its oxides. After being covered with oxides, this new system shows a reduced bandgap than GaTe and exhibits improved properties than counterparts. Moreover, the photodetector based on this special het-erostructure shows a broadband response from ultravio-let to infrared radiation with a responsivity of 1.67 A/W, an external quantum efficiency (EQE) of 391.25%, and a fast response time of 0.4 ms. Benefiting from the in-plane anisotropic crystal structure, the photodetector was observed polarization-sensitive behaviors under the illumination of 532-and 638-nm light. It is suggested that GaTe along with the heterostructure can be seen as promis-ing candidates for polarization-sensitive photodetection operated in a broadband spectrum.