As the fresh blood of 2D family, non‐layered 2D materials (2DNLMs) have demonstrated great potential in the application of next‐generation optoelectronic devices. However, stemming from the weak light absorption brought by atomically thin thickness and the interfacial recombination brought by surface dangling bonds, traditional 2DNLM photodetectors are always accompanied by limited performance. Herein, a structure that integrates Si nanopillar array and non‐layered 2D In2S3 to construct an ultrasensitive photodetector is designed. In particular, periodically Si nanopillars can act as Fabry–Pérot‐enhanced Mie resonators that can effectively control and enhance the light absorption of 2D In2S3. On the other hand, a vertical built‐in electric field is introduced in the In2S3 channel to capture photogenerated holes and leave electrons recycling in In2S3, obtaining a high photogain. Benefiting from these two mechanisms, this proposed photodetector presents a high responsivity of 4812 A W−1 and short rise/decay time of 5.2/4.0 ms at the wavelength of 405 nm. Especially, a high light on–off ratio greater than 106 and a record‐high detectivity of 5.4 × 1015 Jones are achieved, representing one of the most sensitive photodetectors based on 2D materials. This deliberate device design concept suggests an effective scheme to construct high‐performance 2DNLM optoelectronic devices.

Coupling between nanostructures and excitons has attracted great attention for potential applications in quantum information technology.

All‐dielectric (especially silicon) nanostructures that are capable of low‐loss sub‐wavelength light localization are favorable for miniaturized all‐optical or optoelectronic chips. Recently, Si waveguides have been integrated with the 2D transition‐metal dichalcogenides (TMDCs) with atomic thinness and intense light–matter interactions for high‐performance optoelectronic devices. However, further miniaturized and nanoscale optoelectronic devices are highly necessary and can be realized using all‐dielectric Si nanostructures. So far, realizing electrically controlled coupling between all‐dielectric nanostructures and TMDCs is challenging at the subwavelength scale. Here, the electrically controlled optical nanopixels using individual Si nanospheres are reported, which are conventional all‐dielectric units with strong Mie‐type magnetic resonances, wrapped in suspended WS2 monolayers. By applying gate voltages, deformation of the WS2 monolayer occurs as an opening or a closing umbrella. As a result, the scattering intensities are tuned by 40% because of the change in the Mie‐exciton coupling. Simultaneously, a doubled photoluminescence intensity enhancement with a 0.014 eV redshift of excitonic energy is observed, owing to the cooperation of the electromechanics and electrostatic doping. The findings suggest a new approach to build nanoscale optoelectronic devices and display units.

van der Waals (vdW) heterostructures based on vertical-stacking transition metal dichalcogenides (TMDCs) with tunable excitonic energies and spin-valley properties show intriguing optical and optoelectronic applications. Additionally, vdW heterostructures with high refractive indices, excitoninduced Lorentzian dispersion, and controllable structures are ideal building blocks as optical resonators for subwavelength light confinement and effective light−matter interaction, which have not been studied. Herein, we build vdW hetero-nanoslits based on tungsten disulfide (WS 2 ) and hexagonal boron nitride (hBN) multilayers. The multipole optical modes arise from the evolution of electromagnetic near-field distributions through engineering of refractive index and corresponding optical path differences (OPDs). More importantly, the coupling between electromagnetic multipoles with spectral and spatial overlap facilitates the directional scattering with an engineered forwardto-backward (F/B) ratio from 0.1 to 100.0 owing to generalized Kerker effects. Through further combination of WS 2 monolayers and WS 2 /hBN hetero-nanoslits, the photoluminescence (PL) modulation in the range of 50% to 800% is achieved. The enhancement factor and modulation range are comparable to the best performances of single-element plasmonic or dielectric nanostructures. This work provides a different insight into designing nanophotonic devices in the visible range by solely relying on vdW heterostructures.

Controlling excitonic energy transfer in 2D van der Waals (vdW) heterostructures is crucial for photonic and optoelectronic applications. Recent studies suggest that the interlayer energy transfer in vdW heterostructures is strongly correlated with the vertical interlayer spacing. However, the interlayer coupling with large separations (>20 nm) when the radiative energy transfer is dominant has not been studied yet. In this case, excitons as radiative dipole sources are able to control the light field. Here, the thickness dependency of radiative energy transfer in vertical vdW heterostructures of WS2 (tungsten disulfide)/hBN (hexagonal boron nitride)/WS2 is studied. The excitonic emission of WS2/hBN and WS2/hBN/WS2 heterostructures is engineered with the intensity ratios of heterostructures to monolayers ranging from 5% to 250%. More importantly, by changing the stacking order to control whether forward or backward emission is collected, a controllable directivity of the excitonic emission from 0.6 to 6.0 is achieved. In theory, the tunability to high‐index/mid‐index interferences and dipole–dipole far‐field coupling is attributed. The outcomes of the study on the radiative energy transfer of vdW heterostructures containing 1Ls (monolayers) with excitonic effects and MLs (multilayers) with high refractive indices will pave the way toward the realization of all vdW nanophotonics.