Inorganic sheets: Graphene-like MoS2 and WS2 were prepared by three different chemical methods. Examination microscopic techniques revealed that they consist of one or a few layers (see depicted TEM image layers), an atomic-resolution showed layered has hexagonal arrangement Mo S atoms inset).

Most of recent research on layered chalcogenides is understandably focused single atomic layers. However, it unclear if single-layer units are the most ideal structures for enhanced gas-solid interactions. To probe this issue further, we have prepared large-area MoS2 sheets ranging from to multiple layers 300 nm SiO2/Si substrates using micromechanical exfoliation method. The thickness and layering were identified by optical microscope, invoking recently reported specific color contrast,...

Field effect transistors using ultrathin molybdenum disulfide (MoS2) have recently been experimentally demonstrated, which show promising potential for advanced electronics. However, large variations like hysteresis, presumably due to extrinsic/environmental effects, are often observed in MoS2 devices measured under ambient environment. Here, we report the origin of their hysteretic and transient behaviors suggest that hysteresis field is largely absorption moisture on surface intensified by...

Room-temperature, bottom-gate, field-effect transistor characteristics of 2D ultrathin layer GaS and GaSe prepared from the bulk crystals using a micromechanical cleavage technique are reported. The transistors based on active layers demonstrate typical n-and p-type conductance operation along with good ON/OFF ratio electron differential mobility. Detailed facts importance to specialist readers published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or...

Abstract There has been emerging interest in exploring single‐sheet 2D layered structures other than graphene to explore potentially interesting properties and phenomena. The preparation, isolation rapid unambiguous characterization of large size ultrathin layers MoS 2 , GaS, GaSe deposited onto SiO /Si substrates is reported. Optical color contrast identified using reflection optical microscopy for with various thicknesses. these thin correlated atomic force (AFM) Raman spectroscopy...

Anorganische Schichten: Graphenartiges MoS2 und WS2 wurde durch drei verschiedene chemische Methoden hergestellt. Mikroskopische Untersuchungen offenbarten, dass die Strukturen aus einer oder wenigen Schichten aufgebaut sind (siehe TEM-Aufnahme von WS2-Schichten), ein atomar aufgelöstes TEM-Bild zeigt, schichtförmiges eine hexagonale Anordnung Mo- S-Atomen aufweist Einschub).

A comprehensive overview on the recent developments in application of 2D layered inorganic nanomaterials as sensors is presented. Salient features materials different sensing applications<italic>viz.</italic>gas sensing, electrochemical SERS and biosensing photodetection are discussed.

Ultra-thin MoS2 has recently emerged as a promising two-dimensional semiconductor for electronic and optoelectronic applications. Here, we report high mobility (>60 cm2/Vs at room temperature) field-effect transistors that employ unencapsulated single-layer on oxidized Si wafers with low level of extrinsic contamination. While charge transport in the sub-threshold regime is consistent variable range hopping model, monotonically decreasing increasing temperature suggests band-like linear...

High performance chemical sensor is highly desirable to detect traces of toxic gas molecules. Two dimensional (2D) transition metal dichalcogenides (TMDC) semiconducting materials has attracted as high device applications due unique properties such surface volume ratio. Here, we describe the utilization single-layer MoSe2 high-performance room temperature NH3 sensors. Our based shows comprehensible detection down 50 ppm. We also confirmed sensing measurement by recording Raman spectra before...

Recent investigations on two-dimensional black phosphorus material mainly highlight work few atomic layers and multilayers. It is still unknown if the atomically thin sheet an ideal structure for enhanced gas–solid interactions due to its large surface area. To further investigate this concern, we have synthesized layer thick nanosheets of using electrochemical exfoliation method. The morphology thickness nanosheet were identified AFM, TEM, Raman spectroscopy. film device was used gas...

Borophene, an elemental metallic Dirac material is predicted to have unprecedented mechanical and electronic character. Need of substrate ultrahigh vacuum conditions for deposition borophene restricts its large-scale applications significantly hampers the advancement research on borophene. Herein, a facile synthesis freestanding atomic sheets through novel liquid-phase exfoliation reduction oxide demonstrated. Electron microscopy confirms presence β12 , X3 their intermediate phases...

Abstract We report the temperature‐dependent Raman spectra of single‐ and few‐layer MoSe 2 WSe in range 77–700 K. observed linear variation peak positions widths bands arising from contributions anharmonicity thermal expansion. After characterization using atomic force microscopy high‐resolution transmission electron microscopy, temperature coefficients modes were determined. Interestingly, coefficient A 2u mode is larger than that 1g mode, latter being much smaller corresponding same...

Abstract We report here the field emission studies of a layered WS 2 -RGO composite at base pressure ~1 × 10 −8 mbar. The turn on required to draw current density 1 μA/cm is found be 3.5, 2.3 and V/μm for , RGO respectively. enhanced behavior observed nanocomposite attributed high enhancement factor 2978, which associated with surface protrusions single-to-few layer thick sheets nanocomposite. highest ~800 drawn an applied 4.1 from few layers Furthermore, first-principles functional...

In the present investigation, we report a one-step synthesis method of wafer-scale highly crystalline tungsten disulfide (WS2) nanoparticle thin film by using modified hot wire chemical vapor deposition (HW-CVD) technique. The average size WS2 is found to be 25–40 nm over an entire 4 in. wafer quartz substrate. low-angle XRD data shows nature sample along with orientation (002) direction. Furthermore, Raman spectroscopy two prominent phonon vibration modes E12g and A1g at ∼356 ∼420 cm–1,...

We have systematically investigated the temperature dependent Raman spectroscopy behavior of a few layered MoS2 and WS2 nanosheets synthesized using simple hydrothermal method. Our result reveals A1g E12g modes soften as increases from 77 K to 623 K. This can be explained in terms double resonance process which is active single- layer thick nanosheets. The frequency shifts peak broadening provide unambiguous, nondestructive, accurate information WS2. mechanism also applicable characterizing...

Abstract Field emission studies are reported for the first time on layered MoS 2 sheets at base pressure of ∼1 × 10 −8 mbar. The turn‐on field required to draw a current density μ A/cm is found be 3.5 V/ m sheets. values significantly lower than nanoflowers, graphene, and carbon nanotube‐based emitters due high enhancement factor (∼1138) associated with nanometric sharp edges sheet emitter surface. current–time plots show good stability over period 3 h. Owing low planar (sheetlike)...

We investigate the growth mechanism and temperature dependent Raman spectroscopy of chemical vapor deposited large area monolayer MoS₂, MoSe₂, WS₂ WSe₂ nanosheets up to 70 μm in lateral size.

Atomically thin two-dimensional tungsten disulfide (WS2) sheets have attracted much attention due to their potential for future nanoelectronic device applications. We report first experimental investigation on temperature dependent Raman spectra of single-layer WS2 prepared using micromechanical exfoliation. Our spectroscopy results shows that the E(1)2g and A1g modes soften as increases from 77 623 K. The calculated coefficients frequencies 2LA(M), E(1)2g, A1g, A1g(M) + LA(M) were observed...

We report field electron emission investigations on pulsed laser-deposited molybdenum disulfide (MoS2) thin films W-tip and Si substrates. In both cases, under the chosen growth conditions, dry process of laser deposition (PLD) is seen to render a dense nanostructured morphology MoS2, which important for local electric enhancement in application. case MoS2 film silicon (Si), turn-on required draw an current density 10 μA/cm(2) found be 2.8 V/μm. Interestingly, tungsten (W) tip emitter...

Atomically thin two-dimensional (2D) sheets of black phosphorus have attracted much attention due to their potential for future nanoelectronic and photonics device applications. Present investigations deal with the temperature dependent phonon shifts in a few-layer nanosheet sample prepared using micromechanical exfoliation on 300 nm SiO2/Si substrate. The Raman spectroscopy experiments were carried out sample, which depicts softening Ag1, B2g, Ag2 modes as increases from 77 673 K....

Sensing characteristics of few-layer graphenes for NO2 and humidity have been investigated with graphene samples prepared by the thermal exfoliation graphitic oxide, conversion nanodiamond (DG) arc-discharge graphite in hydrogen (HG). The sensitivity is found to be highest DG. Nitrogen-doped HG (n-type) shows increased compared pure HG. observed examined different aliphatic alcohols vary chain length branching.