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Continuous miniaturization of semiconductor devices is the key to boosting modern electronics development. However, this downscaling strategy has been rarely utilized in photoelectronics and photovoltaics. Here, in this work, a full‐van der Waals (vdWs) 1D p‐Te/2D n‐Bi2O2Se heterodiode with a rationally designed nanoscale ultra‐photosensitive channel is reported. Enabled by the dangling bond‐free mixed‐dimensional vdWs integration, the Te/Bi2O2Se type‐II diodes show a high rectification ratio of 3.6 × 104. Operating with 100 mV reverse bias or in a self‐power mode, the photodiodes demonstrate excellent photodetection performances, including high responsivities of 130 A W−1 (100 mV bias) and 768.8 mA W−1 (self‐power mode), surpassing most of the reports of other heterostructures. More importantly, a superlinear photoelectric conversion phenomenon is uncovered in these nanoscale full‐vdWs photodiodes, in which a model based on the in‐gap trap‐assisted recombination is proposed for this superlinearity. All these results provide valuable insights in light–matter interactions for further performance enhancement of photoelectronic devices. [ABSTRACT FROM AUTHOR]

Converting vapor precursors to solid nanostructures via a liquid noble-metal seed is a common vapor deposition principle. However, such a noble-metal-seeded process is excluded from the crystalline halide perovskite synthesis, mainly hindered by the growth mechanism shortness. Herein, powered by a spontaneous exothermic nucleation process (Δ H < 0), the Au-seeded CsPbI 3 nanowires (NWs) growth is realized based on a vapor-liquid-solid (VLS) growth mode. It is energetically favored that the Au seeds are reacted with a Pb vapor precursor to form molten Au-Pb droplets at temperatures down to 212 °C, further triggering the low-temperature VLS growth of CsPbI 3 NWs. More importantly, this Au-seeded process reduces in-bandgap trap states and consequently avoids Shockley-Read-Hall recombination, contributing to outstanding photodetector performances. Our work extends the powerful Au-seeded VLS growth mode to the emerging halide perovskites, which will facilitate their nanostructures with tailored material properties.

Halide hybrid perovskites are attracting considerable attention as highly promising candidates for directly sensing X-ray radiation, but it is challenging to realize passive X-ray detection without an external power supply. However, the bulk photovoltaic effect (BPVE) in ferroelectrics promotes the independent separation of photoexcited carriers. Herein, by dimensionality reconstruction of a pure-two-dimensional (P-2D) monolayered perovskite (CH 3 OC 3 H 9 N) 2 PbBr 4 , we obtained a quasi-two-dimensional (Q-2D) ferroelectric (CH 3 OC 3 H 9 N) 2 CsPb 2 Br 7 . Converting P-2D into Q-2D perovskite stimulates a significant BPVE associated with robust ferroelectricity, as well as an enhanced mobility lifetime product. These features show the potential of the first passive X-ray detector based on ferroelectrics with an impressive sensitivity up to 410 μC Gy -1  cm -2 at zero bias, which is even superior to the value of the state-of-the-art α-Se detector operated at relatively high bias., (© 2021 Wiley-VCH GmbH.)