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.

Neuromorphic machine vision has attracted extensive attention on wide fields. However, both current and emerging strategies still suffer from power/time inefficiency, and/or low compatibility, complex device structure. Here we demonstrate a driving-voltage-free optoelectronic synaptic device using non-volatile reconfigurable photovoltaic effect based on MoTe₂/α-In₂Se₃ ferroelectric p–n junctions. This function comes from the non-volatile reconfigurable built-in potential in the p–n junction that is related to the ferroelectric polarization in α-In₂Se₃. Reconfigurable rectification behavior and photovoltaic effect are demonstrated firstly. Notably, the figure-of-merits for photovoltaic effect like photoelectrical conversion efficiency non-volatilely increases more than one order. Based on this, retina synapse-like vision functions are mimicked. Optoelectronic short-term and long-term plasticity, as well as basic neuromorphic learning and memory rule are achieved without applying driving voltage. Our work highlights the potential of ferroelectric p–n junctions for enhanced solar cell and low-power optoelectronic synaptic device for neuromorphic machine vision.