Reconfigurable devices can be used to achieve multiple logic operation and intelligent optical sensing with low power consumption, which is promising candidates for new generation electronic and optoelectronic integrated circuits. However, the versatility is still limited and need to be extended by the device architectures design. Here, we report an asymmetrically gate two-dimensional (2D) van der Waals heterostructure with hybrid dielectric layer SiO₂/hexagonal boron nitride (h-BN), which enable rich function including reconfigurable logic operation and in-sensor information encryption enabled by both volatile and non-volatile optoelectrical modulation. When the partial gate is grounded, the non-volatile light assisted electrostatic doping endowed partially reconfigurable doping between n-type and p-type, which allow the switching of logic XOR and not implication (NIMP). When the global gate is grounded, additionally taking the optical signal as another input signal, logic AND and OR is realized by combined regulation of the light and localized gate voltage. Depending on the high on/off current ratio approaching 10⁵ and reliable & switchable logic gate, in-sensor information encryption and decryption is demonstrated by manipulating the logic output. Hence, these results provide strong extension for current reconfigurable electronic and optoelectronic devices.

Ternary two-dimentional (2D) materials exhibit diverse physical properties depending on their composition, structure, and thickness. Through forming heterostructures with other binary materials that show similar structure, there can be numerous potential applications of these ternary 2D materials. In this work, we reported the structure of few-layer CrPS₄ by X-ray diffraction, transmission electron microscope, and electron-density distribution calculation. We also demonstrated a new application of the CrPS₄/MoS₂ heterobilayer: visible-infrared photodetectors with type-II staggered band alignment at room temperature. The response of the heterostructure to infrared light results from a strong interlayer coupling that reduces the energy interval in the junction area. Since the intrinsic bandgap of individual components determines wavelengths, the decrease in energy interval allows better detection of light that has a longer wavelength. We used photoluminescence (PL) spectroscopy, Kelvin probe force microscopy (KPFM) under illumination, and electrical transport measurements to verify the photoinduced charge separation between the CrPS₄/MoS₂ heterostructures. At forward bias, the device functioned as a highly sensitive photodetector, as the wavelength-dependent photocurrent measurement achieved the observation of optical excitation from 532 to 1,450 nm wavelength. Moreover, the photocurrent caused by interlayer exciton reached around 1.2 nA at 1,095 nm wavelength. Our demonstration of the strong interlayer coupling in the CrPS₄/MoS₂ heterostructure may further the understanding of the essential physics behind binary-ternary transition metal chalcogenides heterostructure and pave a way for their potential applications in visible-infrared devices.

Two-dimensional (2D) transition-metal dichalcogenide materials (TMDs) alloys have a wide range of applications in the field of optoelectronics due to their capacity to achieve wide modulation of the band gap with fully tunable compositions. However, it is still a challenge for growing alloys with uniform components and large lateral size due to the random distribution of the crystal nucleus locations. Here, we applied a simple but effective promoter assisted liquid phase chemical vapor deposition (CVD) method, in which the quantity ratio of promoter to metal precursor can be controlled precisely, leading to tiny amounts of transition metal oxide precursors deposition onto the substrates in a highly uniform and reproducible manner, which can effectively control the uniform distribution of element components and nucleation sites. By this method, a series of monolayer Nb_1−xW_xSe₂ alloy films with fully tunable compositions and centimeter scale have been successfully synthesized on sapphire substrates. This controllable approach opens a new way to produce large area and uniform 2D alloy film, which has the potential for the construction of optoelectronic devices with tailored spectral responses.

Two-dimensional layered transition metal dichalcogenides (TMDCs) have demonstrated a huge potential in the broad fields of optoelectronic devices, logic electronics, electronic integration, as well as neural networks. To take full advantage of TMDC characteristics and efficiently design the device structures, one of the most key processes is to control their p-/n-type modulation. In this review, we summarize the p-/n-type modulation of TMDCs based on diverse strategies consisting of intrinsic defect tailoring, substitutional doping, surface charge transfer, chemical intercalation, electrostatic modulation, and dielectric interface engineering. The modulation mechanisms and comparisons of these strategies are analyzed together with a discussion of their corresponding device applications in electronics and optoelectronics. Finally, challenges and outlooks for p-/n-type modulation of TMDCs are presented to provide references for future studies.

Strain engineering is proposed to be an effective technology to tune the properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs). Conventional strain engineering techniques (e.g., mechanical bending, heating) cannot conserve strain due to their dependence on external action, which thereby limits the application in electronics. In addition, the theoretically predicted strain-induced tuning of electrical performance of TMDCs has not been experimentally proved yet. Here, a facile but effective approach is proposed to retain and tune the biaxial tensile strain in monolayer MoS₂ by adjusting the process of the chemical vapor deposition (CVD). To prove the feasibility of this method, the strain formation model of CVD grown MoS₂ is proposed which is supported by the calculated strain dependence of band gap via the density functional theory (DFT). Next, the electrical properties tuning of strained monolayer MoS₂ is demonstrated in experiment, where the carrier mobility of MoS₂ was increased by two orders (~ 0.15 to ~ 23 cm²·V^-1·s^-1). The proposed pathway of strain preservation and regulation will open up the optics application of strain engineering and the fabrication of high performance electronic devices in 2D materials.