Two-Dimensional High-Quality Monolayered Triangular WS₂ Flakes for Field-Effect Transistors

Abstract

Large-area uniform of single-crystal tungsten disulfide (WS) is important for advanced optoelectronics based on two-dimensional (2D) atomic crystals. However, difficulties in controlling the interrelated growth parameters restrict its development in devices. Herein, we present the synthesis of triangular monolayered WS flakes with good uniformity and single crystal by adjusting the introduction time of sulfur precursor and the distances between the sources and substrates to control the nucleation density. Investigation of the morphology and structure by transmission electron microscopy and Raman spectroscopy indicates that a series of triangular (side length of 233 μm) monolayered WS flakes shows high-quality structure and homogenous crystallinity. Field-effect transistors based on the fabricated triangular monolayered WS with single crystal demonstrate environmentally stable charge transport with a field-effect mobility of 50.5 cm/V s and current modulation I/ I of ∼10. The results of this study pave the way for the application of monolayered WS in a multitude of 2D-material-based devices.

Space‐Confined Growth of 2D InI Showing High Sensitivity in Photodetection

“…Based on these remarkable outcomes, our InI photodetector proved to be highly efficient with high crystal quality. [ 42,47–49 ]…”

A comprehensive study on the effects of gamma radiation on the physical properties of a two-dimensional WS2monolayer semiconductor

“…It spans a great diversity of atomic structures and physical properties. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Amongst them prominent 2D materials are transition metal dichalcogenides (2D-TMDCs). 1,2 A notable feature of the TMDCs is a transition from an indirect band gap to a direct band gap when thinned from bulk to a monolayer, which enhances significantly photoluminescence (PL) intensity.…”

“…1 Furthermore, tunable electronic properties, structural controllability, and unique spin valley-coupled properties such as valley selective circular dichroism make the TMDCs promising platform for exploring new optoelectronic and valleytronics device applications such as photovoltaic light sensors, 2 photonics, 3 flexible nanoelectronics, 4 energy storage, 5,6 integration with silicon technology, low-loss nanophotonic, 12 and high on/off output current ratio FETs. 13 In addition, the devices based on 2D TMDCs are characterized by small size, light weight and low power consumption. This makes them advantageous for use in space instrumentation.…”

WS2 film on a SiC substrate and its optical properties

“…Recent advances in two-dimensional (2-D) semiconductors, particularly monolayer transition-metal dichalcogenides (TMDs), have attracted rapidly growing scientific interests for next-generation electrical and optoelectronic device applications. [1][2][3][4][5][6][7][8][9][10][11] A single layer of TMDs exhibits a totally new phenomenon, which can lead to 2-D nanoelectronic and nanophotonic applications owing to its unique physical, electrical, and optical properties. [12][13][14][15] Chemical vaporized deposition method was used to synthesize monolayer TMDs [16][17][18][19] mainly; however, magnetron sputtering technique can be used to produce large thin layered TMDs films or even monolayer TMDs.…”

“…21,22 However, the size of most large stable monolayer TMDs is of several hundred micrometers scales. 1,2 It is much easier to have a wafer size thin layer WS 2 film (tens of nm thickness or over), especially in optoelectronic device applications; it is necessary to investigate the optical natures of thin layered TMDs film.…”