Graphene is a promising candidate material for high-speed and ultra-broadband photodetectors. However, graphene-based photodetectors suffer from low photoreponsivity and I(light)/I(dark) ratios due to their negligible-gap nature and small optical absorption. Here, a new type of graphene/InAs nanowire (NW) vertically stacked heterojunction infrared photodetector is reported, with a large photoresponsivity of 0.5 AW(-1) and I(light)/I(dark) ratio of 5 × 10(2), while the photoresponsivity and I(light)/I(dark) ratio of graphene infrared photodetectors are 0.1 mAW(-1) and 1, respectively. The Fermi level (E(F)) of graphene can be widely tuned by the gate voltage owing to its 2D nature. As a result, the back-gated bias can modulate the Schottky barrier (SB) height at the interface between graphene and InAs NWs. Simulations further demonstrate the rectification behavior of graphene/InAs NW heterojunctions and the tunable SB controls charge transport across the vertically stacked heterostructure. The results address key challenges for graphene-based infrared detectors, and are promising for the development of graphene electronic and optoelectronic applications.

"One key to one lock" hybrid sensor configuration is rationally designed and demonstrated as a direct effective route for the target-gas-specific, highly sensitive, and promptly responsive chemical gas sensing for room temperature operation in a complex ambient background. The design concept is based on three criteria: (i) quasi-one-dimensional metal oxide nanostructures as the sensing platform which exhibits good electron mobility and chemical and thermal stability; (ii) deep enhancement-mode field-effect transistors (E-mode FETs) with appropriate threshold voltages to suppress the nonspecific sensitivity to all gases (decouple the selectivity and sensitivity away from nanowires); (iii) metal nanoparticle decoration onto the nanostructure surface to introduce the gas specific selectivity and sensitivity to the sensing platform. In this work, using Mg-doped In2O3 nanowire E-mode FET sensor arrays decorated with various discrete metal nanoparticles (i.e., Au, Ag, and Pt) as illustrative prototypes here further confirms the feasibility of this design. Particularly, the Au decorated sensor arrays exhibit more than 3 orders of magnitude response to the exposure of 100 ppm CO among a mixture of gases at room temperature. The corresponding response time and detection limit are as low as ∼4 s and ∼500 ppb, respectively. All of these could have important implications for this "one key to one lock" hybrid sensor configuration which potentially open up a rational avenue to the design of advanced-generation chemical sensors with unprecedented selectivity and sensitivity.

With the Moore's law hitting the bottleneck of scaling-down in size (below 10 nm), personalized and multifunctional electronics with an integration of 2D materials and self-powering technology emerge as a new direction of scientific research. Here, a tunable tribotronic dual-gate logic device based on a MoS field-effect transistor (FET), a black phosphorus FET and a sliding mode triboelectric nanogenerator (TENG) is reported. The triboelectric potential produced from the TENG can efficiently drive the transistors and logic devices without applying gate voltages. High performance tribotronic transistors are achieved with on/off ratio exceeding 106 and cutoff current below 1 pA μm . Tunable electrical behaviors of the logic device are also realized, including tunable gains (improved to ≈13.8) and power consumptions (≈1 nW). This work offers an active, low-power-consuming, and universal approach to modulate semiconductor devices and logic circuits based on 2D materials with TENG, which can be used in microelectromechanical systems, human-machine interfacing, data processing and transmission.

In the past decade, high-performance, low-cost, and robust photodetectors have become one of the key components for a wide range of commercial systems, including environment and security monitoring, [1] wearable electronics, [2] free-space communications, [3] and biomedical diagnostics, [4] etc. As inspired by these applications, various emerging materials, such as quantum dots, [5] carbon nanotubes, [6] graphene, [7] and transition-metal dichalcogenides, [8] are extensively explored for the efficient photodetection. In particular, organic-inorganic hybrid perovskites (OHPs) are lately considered as the superior light-harvesting materials for photodetectors owning to their unique advantages of high optical absorption coefficient, long exciton diffusion length, and low binding energy of exciton. [9][10][11] Although these OHP materials can be easily prepared by cost-effective solution-based processes to meet the ever-increasing consumer demands for large-area and flexible optoelectronics, their photodetectors usually exhibit the relatively low responsivity because of the limited carrier mobility as well as the absence of photoconductive gain (G) mechanism that can induce multiple charge carriers by one incident photon.In order to tackle these insufficient device performances, hybrid phototransistors by simply integrating perovskites (PVKs) with different 2D materials (e.g., graphene, [12] black phosphorus, [13,14] MoS 2 , [15] and WSe 2 [16] ) have been proposed and demonstrated. By using these hybrid heterostructures, upon illumination, the photoexcited charge carriers can be spatially separated at the hetero-interface in order to prolong their carrier lifetimes, which subsequently improves the photoconductive gain of the system. However, there are still significant concerns regarding the high fabrication cost and low production yield of 2D materials for the realization of such photodetectors. At the same time, due to the low formation energy, PVK photodetectors are generally susceptible to degradation upon air and moisture exposure. In this case, tremendous efforts have then been invested to explore effective approaches to enhance the ambient-stability of these devices. [17,18] Among many latest advances, recent breakthroughs in achieving the 2D Ruddlesden-Popper phase of PVKs with the chemical formula of (RNH 3 ) 2 (A) n−1 M n X 3n+1 , where RNH 3 is a large size or long-chain organic cation, A is a regular cation, M is a divalent Organic-inorganic hybrid perovskites (PVKs) have recently emerged as attractive materials for photodetectors. However, the poor stability and low electrical conductivity still restrict their practical utilization. Owing to the quantum-well feature of two-dimensional (2D) Ruddlesden-Popper PVKs (2D PVKs), a promising quasi-2D PVK/indium gallium zinc oxide (IGZO) heterostructure phototransistor can be designed. By using a simple ligand-exchange spin-coating method, quasi-2D PVK fabricated on flexible substrates exhibits a desirable type-II energy band alignment, which facilitates effect...