An emerging electronic material as one of transition metal dichalcogenides (TMDCs), tungsten disulfide (WS2) can be exfoliated as an atomically thin layer and can compensate for the drawback of graphene originating from a gapless band structure. A direct bandgap, which is obtainable in single-layer WS2, is an attractive characteristic for developing optoelectronic devices, as well as field-effect transistors. However, its relatively low mobility and electrical characteristics susceptible to environments remain obstacles for the use of device materials. Here, we demonstrate remarkable improvement in the electrical characteristics of single-layer WS2 field-effect transistor (SL-WS2 FET) using chemical vapor deposition (CVD)-grown hexagonal BN (h-BN). SL-WS2 FET sandwiched between CVD-grown h-BN films shows unprecedented high mobility of 214 cm2/Vs at room temperature. The mobility of a SL-WS2 FET has been found to be 486 cm2/Vs at 5 K. The ON/OFF ratio of output current is ~107 at room temperature. Apart from an ideal substrate for WS2 FET, CVD-grown h-BN film also provides a protection layer against unwanted influence by gas environments. The h-BN/SL-WS2/h-BN sandwich structure offers a way to develop high-quality durable single-layer TMDCs electronic devices.

Graphene and hexagonal boron nitride (hBN) have shown fascinating features in spintronics due to their metallic and tunneling behaviors, respectively. In this work, we report for the first time room temperature spin valve effect in NiFe/Gr–hBN/Co configuration.

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Improvement of the electrical and photoelectric characteristics is essential to achieve an advanced performance of field-effect transistors and optoelectronic devices. Here we have developed a doping technique to drastically improve electrical and photoelectric characteristics of single-layered, bi-layered and multi-layered WS2 field-effect transistors (FET). After illuminating with deep ultraviolet (DUV) light in a nitrogen environment, WS2 FET shows an enhanced charge carrier density, mobility and photocurrent response. The threshold voltage of WS2 FET shifted toward the negative gate voltage, and the positions of E and A1g peaks in Raman spectra shifted toward lower wavenumbers, indicating the n-type doping effect of the WS2 FET. The doping effect is reversible. The pristine characteristics of WS2 FET can be restored by DUV light illumination in an oxygen environment. The DUV-driven doping technique in a gas environment provides a very stable, effective, easily applicable way to enhance the performance of WS2 FET.

has been dominated by various singlejunction solar cells with a practical efficiency of up to 22%. To date, photovoltaic devices with high efficiency, long lifetime, compact size, and low cost as a highlighter key still require more attention. Current commercially available solar panels based on mono-crystalline silicon (c-Si) wafers for single-junction solar cells dominate the current PV market. So far, laboratory solar cells have been fabricated with an efficiency of nearly 26.3%. Even though the energy conversion efficiency reaches a maximum value of ≈33.5% for the upper theoretical energy conversion efficiency with a bandgap of 1.15 eV. [2,3] Since Russell Shoemaker Ohl's experiment over 80 years ago, the p-n junction has become an important part of modern electronics and optoelectronics. [4] This device is constructed by connecting two types of dopants, n-type and p-type, together. [5,6] As a result, an intrinsic electric field is present at the interface, which could be employed by electron-hole pair separation created by the absorption of incoming photons. The photovoltaic (PV) effect is the phenomenon of voltage and current generation in materials while they are illuminated. Non-centrosymmetric materials are made up of only a single component. But a photocurrent is an electric current that can also be made when there is no built-in potential It is highly desirable for exploring and discovering new materials and outcome-based approaches to exceed the Shockley-Queisser limit for singlejunction photovoltaic cells. Low-dimensional piezoelectric materials have the potential to generate the optoelectronic phenomenon called the bulk photovoltaic effect, which is not limited by the theoretical limit for solar radiation into electricity conversion. The recent development of 2D materials has demonstrated that by using the bulk photovoltaic effect (BPVE) for crystals lacking inversion symmetry, it is possible to overcome this limit. So far, the exploration of p-n junction designs has been addressed in several review articles. However, the mechanism of BPVE differs from traditional p-n junctionbased photovoltaics in 2D materials. In this focused review, various concepts regarding the shift-current response are explored, both from theoretical and experimental points of view, which are generated in the framework of deformed 2D materials. Finally, prospective approaches for building BPVEbased next-generation solar cells using ultrathin 2D materials are presented. These materials are expected to work better than current methods of turning energy into electricity.

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The two-dimensional (2D) layered electronic materials of transition metal dichalcogenides (TMDCs) have been recently proposed as an emerging canddiate for spintronic applications. Here, we report the exfoliated single layer WS2-intelayer based spin valve effect in NiFe/WS2/Co junction from room temperature to 4.2 K. The ratio of relative magnetoresistance in spin valve effect increases from 0.18% at room temperature to 0.47% at 4.2 K. We observed that the junction resistance decreases monotonically as temperature is lowered. These results revealed that semiconducting WS2 thin film works as a metallic conducting interlayer between NiFe and Co electrodes.

Schottky-barrier diodes have great importance in power management and mobile communication because of their informal device technology, fast response and small capacitance.