High-quality two-dimensional tellurium flakes grown by high-temperature vapor deposition

Elemental two-dimensional (2D) tellurium (Te) possesses fascinating properties such as high mobility, strong anisotropy and strong infrared response, which show great potential for various applications. However, the fabrication of large-area and high-quality 2D Te flakes by vapor deposition remains challenging. Herein, we developed a strategy of using In2Te3 powder as the source for high-temperature vapor deposition of 2D tellurium flakes. The synthesized regular Te flakes have a lateral length larger than 100 mu m and possess excellent optoelectronic properties. The thin Te flakes exhibit a low electrical resistivity down to 42 mu omega m and a high field-effect hole mobility up to 850 cm(2) V s(-1). The photodetector based on 2D Te flakes shows a wide response to visible light, with an ultrahigh photoresponsivity of 1.04 x 10(4) A W-1 under illumination of a 405 nm laser. These figures-of-merits of the 2D Te device are prominent compared with those of previously reported Te devices, indicating the very high material quality of our Te flakes synthesized by the proposed growth strategy.