One-step method to simultaneously synthesize separable Te and GeTe nanosheets

The chemical vapor deposition (CVD) method has been widely used to synthesize high-quality two-dimensional (2D) materials. However, just one type of product can be synthesized by general CVD at one time. Here, we demonstrate a one-step CVD method to simultaneously grow two types of products. Importantly, the products can be completely separated by selecting the deposition region. In detail, the controllable and completely separable growth for α-GeTe and Te nanosheets was realized by using one precursor-GeTe powder through the atmospheric pressure CVD (APCVD) approach. High crystal quality of the as-grown α-GeTe nansosheets and Te nanosheets have been proved by the high-resolution transmission electron microscopy (HRTEM) characterization. Further, the field-effect-transistor (FET) based on α-GeTe nanosheet manifests that the as-grown α-GeTe nanosheet is a degenerate semiconductor due to the intrinsic Ge vacancies. Additionally, Te-based FET devices indicate that the good electrical performance of the as-grown Te nanosheet, such as high mobility of 900 cm²·V⁻¹·s⁻¹ (at room temperature), high on/off ratio of > 10 ⁶ (at 77 K), and good air-stability. The developed one-step CVD method shows the huge potentials for high-efficiency and high-quality material growth.