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The exponential development in quantum phenomena is directly correlated with the decreasing size of nano‐semiconductor transistors. Consequently, the use of a quantum structure that deviates from traditional transistor types becomes imperative. Electrostatically defined nanoscale devices within 2D semiconductor heterostructures serve as foundational elements for diverse quantum electrical circuits. Van der Waals heterostructures, distinguished by atomically flat interfaces and inherent 2D characteristics, offer advantages such as large‐scale uniformity, flexibility, and portability over conventional bulk semiconductor heterostructures. Herein, the intricate electronic behavior of a MoS2/WSe2 encapsulated heterostructure governed by split‐gate and middle‐gate configurations is investigated, revealing a distinctive step‐like current profile at a low temperature of 77 K. The observed four regimes in the current highlight the impact of quantum confinement induced by reduced lateral dimensions, coupled with precise electrostatic confinement controlled by gate voltages. The temperature dependence of the phenomena emphasizes the role of thermal effects on carrier scattering mechanisms. In addition, the pinch‐off characteristics with different temperatures, middle‐gate voltages, and drain biases are explored. This study contributes to a deeper understanding of electrostatic effects in 2D transition metal dichalcogenide heterostructures and holds promise for the development of advanced electronic devices with tailored confinement for enhanced functionalities. [ABSTRACT FROM AUTHOR]

Diode characteristics of transition metal dichalcogenides are studied extensively owing to their electrical and optical properties. In particular, the Schottky barrier diode (SBD) structure has advantages, such as its small leakage current and power consumption, over conventional p–n diodes. This study develops an SBD system using n‐type tungsten disulfide (WS2). By depositing a low work function In (ΦIn = 4.1 eV) and high work function Au (ΦAu = 5.1 eV) on n‐type WS2, the diode characteristics are demonstrated to be close to an ideal diode. The In–Au contacts are measured, and SBD characteristics are confirmed with a 1.02 ideality factor at a zero back‐gate voltage at room temperature and a rectification ratio up to 5 × 102, even at a low temperature (77 K), indicating almost ideal diode properties. In addition, the In electrodes exhibited improved electrical properties, with a high on/off ratio of 107, mobility that is 100 times higher, and Schottky barrier height that is 20 times lower than that of Au electrodes. [ABSTRACT FROM AUTHOR]

Manipulation of Ohmic contacts in 2D transition metal dichalcogenides for enhancing the transport properties and enabling its application as a practical device has been a long‐sought goal. In this study, n‐type tungsten disulfide (WS2) single atomic layer to improve the Ohmic contacts of the p‐type molybdenum ditelluride (MoTe2) material is covered. The Ohmic properties, based on the lowering of Schottky barrier height (SBH) owing to the tunneling barrier effect of the WS2 monolayer, are found to be unexpectedly excellent at room temperature and even at 100 K. The improved SBH and contact resistances are 3 meV and 1 MΩ µm, respectively. The reduction in SBH and contact resistance is confirmed with temperature‐dependent transport measurements. This study further demonstrates the selective carrier transport across the MoTe2 and WS2 layers by modulating the applied gate voltage. This WS2/MoTe2 heterostructure exhibits excellent gate control over the currents of both channels (n‐type and p‐type). The on/off ratios for both the electron and hole channels are calculated as 107 and 106, respectively, indicating good carrier type modulation by the electric field of the gate electrode. The Ohmic contact resistance using the tunneling of the atomic layer can be applied to heterojunction combinations of various materials. [ABSTRACT FROM AUTHOR]

Unintentionally formed nanocrystalline graphene (nc-G) can act as a useful seed for the large-area synthesis of a hexagonal boron nitride (h-BN) thin film with an atomically flat surface that is comparable to that of exfoliated singlecrystal h-BN. A wafer-scale dielectric h-BN thin film was successfully synthesized on a bare sapphire substrate by assistance of nc-G, which prevented structural deformations in a chemical vapor deposition process. The growth mechanism of this nc-G-tailored h-BN thin film was systematically analyzed. This approach provides a novel method for preparing high-quality two-dimensional materials on a large surface. [ABSTRACT FROM AUTHOR]

In 2D materials, tungsten diselenide (WSe2) has great potential for optical and electronic devices. However, the quality of WSe2 crystals, determined by defects and grain boundaries, currently restricts its performance in controlling carrier‐transport properties. Consequently, the most significant issue achieves superior growth of WSe2 crystals and appropriate metal contacts. Herein, a doping‐free approach to manipulate the polarity of WSe2 transistors by utilizing distinct metal contacts is presented. WSe2 field‐effect transistors are examined employing low‐ and high‐work function metals. In these findings, a transition in polarity from n‐type for In and Cr to p‐type for Pd and Au is demonstrated, showcasing remarkably high on/off ratios (≈107) and mobilities (≈117 cm2 V−1 s−1) at room temperature. This straightforward polarity control technique can be further extended by utilizing contact architecture‐based research in other 2D materials for future nano‐electrical and optoelectronic devices. [ABSTRACT FROM AUTHOR]