Wide-Spectrum Polarization-Sensitive Photodetector Based on Spontaneous GaTe/Ga2(TexO1-x)5 Heterostructure

Abstract

Low-dimensional semiconductor materials with in-plane anisotropy have attracted increasing attention due to the novel physicochemical properties induced by the special lattice structure. Among III-group metal chalcogenides, GaS, GaSe, and In <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{2}}$</tex-math> </inline-formula> Se <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{3}}$</tex-math> </inline-formula> have been reported impressive performances in microelectronics, optoelectronics, and ferroelectronics. Therefore, the investigation on the III-group chalcogenides and their heterostructures is important for diverse applications with promising functionalities. Gallium telluride (GaTe), as a typical III-group chalcogenide 2-D semiconductor with in-plane anisotropy, can be oxidized in atmosphere, thus forming a spontaneous van der Waals heterostructure consisting 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 heterostructure shows a broadband response from ultraviolet 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 promising candidates for polarization-sensitive photodetection operated in a broadband spectrum.