Gate‐Modulated Polarity Transition and Polarization‐Sensitive Photodetection Enabled by Sandwiching Anisotropic GeSe in vdW Heterojunction

The ability to modulate the polarity of carrier transport and photo‐response in assembled heterostructure devices remains a huge challenge for the development of multifunctional optoelectronics. Herein, a polarity‐switchable and polarization‐sensitive photodetector is developed based on a van der Waals (vdW) MoTe 2 /GeSe/MoS 2 sandwich heterostructure. By varying the gate voltage, an anti‐bipolar transfer characteristic is obtained with significant peak‐valley current ratio (PVCR) exceeding 10 4 , showing the extraordinary potential to realize electronic functions in logic circuits. Under 635 nm laser irradiation, the device exhibits a gate‐controlled polarity transition of photocurrent, namely, the sign reversal of photocurrent occurs by changing the gate voltage. Furthermore, the device achieves broadband photovoltaic effect and high photodetection performance with responsivity ( R ) of 723 mA·W −1 , noise spectral density ( S n ) of 1 fA Hz −1/2 , and specific detectivity ( D * ) of 2.3×10 12 Jones in the absence of external bias, which greatly outperforms the MoTe 2 /MoS 2 device. Leveraging the in‐plane anisotropic structure of GeSe, the device is also endowed with an additional capability of polarization‐sensing for linearly polarized laser, possessing a high polarization ratio (PR) value of 11.2. Thus, this work proposes an effective and facile strategy to realize the gate‐modulated polarity transition and polarization‐sensitive photodetection, offering a broad perspective for multifunctional integrated applications.