A self-driven photosensor with signal-reversal response has the potential to work as a photodetector in complex environments with multiple signals owing to better signal recognition and enhanced signal-processing efficiency. Herein, a metal-semiconductor-metal photodetector based on ambipolar WSe₂ with two electrodes comprising two-dimensional (2D) van der Waals (vdWs) metal Fe₃GeTe₂ and semimetal graphene was proposed to form an asymmetrical metal-contacted architecture with different Schottky barrier heights. The regulating gate field-induced Fermi level shift in WSe₂ can be used to manipulate the WSe₂ channel’s carrier type, resulting in a polarity-reversible photodetector without a bias voltage. Furthermore, the photovoltaic effect can be observed from wavelengths of 450 nm (visible) to 850 nm (infrared) without external voltage. The large open voltage is −0.177 V and short-circuit current is 17 nA under a 650-nm excitation wavelength. The reported WSe₂-based photodetector exhibits excellent properties under zero bias, including a large photo-to-dark current ratio greater than 10⁶ with dark current less than 1 fA, photovoltaic performance with an external quantum efficiency of 27.14%, an excellent detectivity of 3.4×10¹⁰ Jones, and a high responsivity of 116.38 mA/W. Rapid electron transfer occurs at the interface between WSe₂ and vdWs electrodes, resulting in a 370-µs response speed owing to the clean and nondestructive interfaces between vdWs metals and WSe₂. This study demonstrates the wide application prospect of the vdWs metal Fe₃GeTe₂ as an electrode forming a Schottky junction for realizing a photodetector without an external voltage and accelerates the development of 2D photosensors with various working modes.

由于更好的信号识别和增强的信号处理效率，具有信号反转响应的自驱动光电传感器有可能在具有多个信号的复杂环境中用作光电探测器。在此，提出了一种基于双极 WSe ₂的金属-半导体-金属光电探测器，该探测器具有两个电极，包括二维 (2D) 范德华 (vdWs) 金属 Fe ₃ GeTe ₂和半金属石墨烯，以形成具有不同结构的不对称金属接触结构。肖特基势垒高度。_{WSe 2}中的调节栅极场引起的费米能级位移可用于操纵 WSe ₂通道的载流子类型，导致极性可逆光电探测器没有偏置电压。此外，在没有外加电压的情况下，可以从 450 nm（可见光）到 850 nm（红外）的波长范围内观察到光伏效应。在 650 nm 激发波长下，大开路电压为 -0.177 V，短路电流为 17 nA。所报道的基于WSe ₂的光电探测器在零偏压下表现出优异的性能，包括大于10 ⁶的大光暗电流比和小于1 fA的暗电流，具有27.14%的外量子效率的光伏性能，出色的探测能力3.4×10 ¹⁰琼斯，和 116.38 mA/W 的高响应度。快速电子转移发生在 WSe _{2之间的界面}和 vdWs 电极，由于 vdWs 金属和 WSe ₂之间的清洁和非破坏性界面，导致 370-µs 的响应速度。本研究证明了vdWs金属Fe ₃ GeTe ₂作为形成肖特基结的电极在实现无需外加电压的光电探测器方面具有广阔的应用前景，并加速了具有多种工作模式的二维光电传感器的发展。