Abstract2D‐layered materials and van der Waals heterostructures (vdWHs) have attracted intense interests in optoelectronic applications. However, the performance of photovoltaic effect based on vdWHs is still unsatisfactory, which is subjected to many factors, including settled small built‐in potentials and low light absorptions. Here, a pronounced photovoltaic effect is reported in MoTe2/(C4H9NH3)2(CH3NH3)2Pb3I10/α‐In2Se3 ferroelectric p–i–n vdWHs. An all‐dry transfer method held in an inert environment is utilized to ensure a good materials’ stability and high interfacial quality. The short‐circuit current density can increase three orders to 38 mA cm−2 by introducing perovskite; hence, the device works as a sensitive self‐powered photodetector with a photo on/off ratio of 2.4 × 105, a detectivity of 1.2 × 1012 Jones, and response times of 730 µs/620 µs. Moreover, the short‐circuit current density increases more than 25 times by enhancing the built‐in potential through programming the ferroelectric polarization of α‐In2Se3. In total, short‐circuit current density as high as 468 mA cm−2 is reached, which is one‐to‐two orders higher than that of typical lateral vdWHs. This work demonstrates the potential of high‐performance optoelectronic devices based on ferroelectric van der Waals p–i–n heterostructures.

All-inorganic CsPbI3 halide perovskite has become a hot research topic for applications in next-generation optoelectronic devices. However, the main limitations are the high-temperature synthesis and poor phase stability. In this...

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Two-dimensional semiconductors have great potential for beyond-silicon electronics. However, because of the lack of controllable doping methods, Fermi level pinning, and van der Waals (vdW) gaps at the metal–semiconductor interfaces, these devices exhibit high electrical contact resistances, restricting their practical applications. Here, we report a general contact-resistance-lowering strategy by constructing vertical metal–semiconductor–metal memristor structures at the contact regions and setting them into a nonvolatile low-resistance state through a memristive forming process. Through this, we reduce the contact resistances of MoS2 field-effect transistors (FETs) by at least one order of magnitude and improve the on-state current densities of MoTe2 FETs by about two orders of magnitude. We also demonstrate that this strategy is applicable to other two-dimensional semiconductors, including MoSe2, WS2, and WSe2, and a variety of contact metals, including Au, Cu, Ni, and Pd. The good stability and universality indicate the great potential for technological applications.