In recent years, two-dimensional materials based tunneling heterojunctions are emerging as a multi-functional architecture for logic circuits and photodetection owing to flexibilible stacking, optical sensitivity, tunable detection band and highly...

Abstract2D van der Waals (vdWs) heterostructure‐based multifunctional field effect transistor (FET) has brought about novel physical phenomena. Impressively, anti‐ambipolar characteristic is one of the basis logic functions being used in multi‐valued inverters, which is analogous to negative differential resistance (NDR)‐based transistor. Here, the tunable current‐transport and self‐driven optoelectrical properties of vertically stacked multilayer GeSe/SnS2 heterostructure are reported. In particular, it allows to be switched from n‐type‐dominant behavior to anti‐ambipolar operation regime (a large peak‐to‐valley ratio (PVR) of 1.5 × 103) as a result of different band‐bending under various bias. Under light‐doping engineering, the inverted V‐shaped peak is distinctly shifted because of the higher carrier recombination probability of p‐GeSe component. Besides, for photovoltaic performances, the device exhibits an ultralow dark current of ≈30 fA, a maximum responsivity of 130 mA W−1, and high Ion/Ioff ratio of ≈105 under 532 nm because of the large band offset and the efficient carrier separation process. Meanwhile, the polarization sensitivities can reach 1.9 at 405 nm and 2.6 at 635 nm. It is found that the polarity‐switchable behavior and self‐driven photodetection performance in GeSe/SnS2 vdWs FET can hopefully broaden and simplify the multifunctional integrated devices in the future.

Polarization-sensitive photodetectors in the infrared range have attracted considerable attention because of their unique and wide application prospects in polarization sensors and remote sensing. However, it is challenging to achieve short-wave infrared polarization detection as most polarization-sensitive photodetectors are based on transition-metal dichalcogenide (TMD) materials with in-plane symmetric crystal structure and sizable band gap (1–2 eV). In this work, we design a type-II GeAs/WS2 heterojunction realizing superior self-driven polarization-sensitive photodetection in the short-wave infrared region. The device shows obvious rectifying behavior with a rectification ratio of 1.5 × 104 in the dark and excellent photoresponse characteristics in a broad spectral range. Accordingly, the high responsivity of 509 mA/W, large on/off ratio of 103, a high EQE of 99.8%, and a high specific detectivity of 1.08 × 1012 Jones are obtained under 635 nm laser irradiation. Taking advantage of the narrow band gap of GeAs with an anisotropic structure, the detection spectral coverage can be extended from the visible to the short-wave infrared range (635–1550 nm). Further, the GeAs/WS2 heterojunction shows high polarization sensitivity with an anisotropic photocurrent ratio of 4.5 and 3.1 at zero bias under 1310 and 1550 nm laser irradiation, respectively, which is much higher than that of reported polarization-sensitive photodetectors in the infrared region. This work provides an effective route using low-symmetry 2D materials with narrow band gap and anisotropic structure to design van der Waals (vdW) heterojunctions, realizing multifunctional optoelectronics for rectifying, photovoltaics, and polarization-sensitive photodetectors with spectral coverage up to 1550 nm.