Two-Dimensional Monolayer MX2 (M=Mo, W; X=S, Se) Synthesis, Characterization and Device Applications

2015 ◽  
Author(s):  
Bin Xiang ◽  
Lei Yang ◽  
Jian Huang ◽  
Qi Fu
Keyword(s):  
Semiconductor Device ◽  
Spherical Aberration ◽  
Ambient Pressure ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Two Dimensional ◽  
Large Area ◽  
Scanning Transmission ◽  
Device Applications ◽  
Atomic Analysis

Recently two-dimensional layered semiconductors with promising electronic and optical properties, have opened up a new way for applications in atomically thin electronics and optoelectronics. Here we demonstrate large area synthesis of monolayer MoS2 and WSe2 using a chemical vapor deposition method at ambient pressure. The atomic analysis of the as-grown monolayer was conducted by spherical-aberration-corrected high resolution scanning transmission electron microscopy and atomic force microscopy. Raman spectroscopy was utilized to identify the monolayer configuration of the as-grown samples. Strong photoluminescence peaks at a visible wavelength were observed at room temperature in the as-grown monolayer samples. The mobility and carrier concentrations were calculated in as-grown monolayer-based transistor devices. The emergency of these two dimensional materials provides grand possibilities for future semiconductor device applications.

Water-assisted controllable growth of atomically thin WTe2 nanoflakes by chemical vapor deposition based on precursor design and substrate engineering strategies

2022 ◽  
Author(s):  
Guoliang Zhou ◽  
Hui Gao ◽  
Jin Li ◽  
Xiaoyue He ◽  
Yanbing He ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Ambient Pressure ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Quantum Spin ◽  
Chemical Vapor Deposition Method ◽  
Large Area ◽  
Substrate Engineering ◽  
Controllable Growth

Abstract WTe2 nanostructures have intrigued much attention due to their unique properties, such as large non-saturating magnetoresistance, quantum spin Hall effect and topological surface state. However, the controllable growth of large-area atomically thin WTe2 nanostructures remains a significant challenge. In the present work, we demonstrate the controllable synthesis of 1T’ atomically thin WTe2 nanoflakes (NFs) by water-assisted ambient pressure chemical vapor deposition method based on precursor design and substrate engineering strategies. The introduction of water during the growth process can generate a new synthesized route by reacting with WO3 to form intermediate volatile metal oxyhydroxide. Using WO3 foil as the growth precursor can drastically enhance the uniformity of as-prepared large-area 1T’ WTe2 NFs compared to WO3 powders. Moreover, highly oriented WTe2 NFs with distinct orientations can be obtained by using a-plane and c-plane sapphire substrates, respectively. Corresponding precursor design and substrate engineering strategies are expected to be applicable to other low dimensional transition metal dichalcogenides, which are crucial for the design of novel electronic and optoelectronic devices.

Large-area niobium disulfide thin films as transparent electrodes for devices based on two-dimensional materials

Nanoscale ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 1056-1062 ◽  
Author(s):  
Hunyoung Bark ◽  
Yongsuk Choi ◽  
Jaehyuck Jung ◽  
Jung Hwa Kim ◽  
Hyukjoon Kwon ◽  
...  
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Two Dimensional ◽  
Deposition Method ◽  
Transparent Electrodes ◽  
Large Area ◽  
Two Dimensional Materials ◽  
Niobium Disulfide

Large-area NbS2 films have been synthesized by using the chemical vapor deposition method and exhibited their potential as transparent electrodes for 2D semiconductor devices.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

scholarly journals Thermodynamics Controlled Sharp Transformation from InP to GaP Nanowires via Introducing Trace Amount of Gallium

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhenzhen Tian ◽  
Xiaoming Yuan ◽  
Ziran Zhang ◽  
Wuao Jia ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Driving Force ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Nanowire Growth ◽  
Calphad Approach ◽  
Deposition Method ◽  
Large Area ◽  
Growth Phenomenon

AbstractGrowth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth.

scholarly journals Two-dimensional iodine-monofluoride epitaxy on WSe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yung-Chang Lin ◽  
Sungwoo Lee ◽  
Yueh-Chiang Yang ◽  
Po-Wen Chiu ◽  
Gun-Do Lee ◽  
...  
Keyword(s):  
Density Functional ◽  
Surface Passivation ◽  
Hexagonal Lattice ◽  
Chemical Vapor ◽  
Growth Promoter ◽  
Two Dimensional ◽  
Epitaxial Relationship ◽  
Chemical Vapor Deposition Growth ◽  
Scanning Transmission ◽  
Great Possibility

AbstractInterhalogen compounds (IHCs) are extremely reactive molecules used for halogenation, catalyst, selective etchant, and surface modification. Most of the IHCs are unstable at room temperature especially for the iodine-monofluoride (IF) whose structure is still unknown. Here we demonstrate an unambiguous observation of two-dimensional (2D) IF bilayer grown on the surface of WSe2 by using scanning transmission electron microscopy and electron energy loss spectroscopy. The bilayer IF shows a clear hexagonal lattice and robust epitaxial relationship with the WSe2 substrate. Despite the IF is known to sublimate at −14 °C and has never found as a solid form in the ambient condition, but surprisingly it is found stabilized on a suitable substrate and the stabilized structure is supported by a density functional theory. This 2D form of IHC is actually a byproduct during a chemical vapor deposition growth of WSe2 in the presence of alkali metal halides as a growth promoter and requires immediate surface passivation to sustain. This work points out a great possibility to produce 2D structures that are unexpected to be crystallized or cannot be obtained by a simple exfoliation but can be grown only on a certain substrate.

Photoelectron Spectroscopic Imaging and Device Applications of Large-Area Patternable Single-Layer MoS2Synthesized by Chemical Vapor Deposition

ACS Nano ◽  
2014 ◽  
Vol 8 (5) ◽  
pp. 4961-4968 ◽  
Author(s):  
Woanseo Park ◽  
Jaeyoon Baik ◽  
Tae-Young Kim ◽  
Kyungjune Cho ◽  
Woong-Ki Hong ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Spectroscopic Imaging ◽  
Large Area ◽  
Device Applications

scholarly journals Imaging of local structures affecting electrical transport properties of large graphene sheets by lock-in thermography

2019 ◽  
Vol 5 (2) ◽  
pp. eaau3407 ◽  
Author(s):  
H. Nakajima ◽  
T. Morimoto ◽  
Y. Okigawa ◽  
T. Yamada ◽  
Y. Ikuta ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Chemical Vapor ◽  
Atomic Scale ◽  
Electrical Transport Properties ◽  
Large Area ◽  
Graphene Layers ◽  
Device Applications ◽  
Chemical Vapor Deposition Graphene ◽  
Lock In

The distribution of defects and dislocations in graphene layers has become a very important concern with regard to the electrical and electronic transport properties of device applications. Although several experiments have shown the influence of defects on the electrical properties of graphene, these studies were limited to measuring microscopic areas because of their long measurement times. Here, we successfully imaged various local defects in a large area of chemical vapor deposition graphene within a reasonable amount of time by using lock-in thermography (LIT). The differences in electrical resistance caused by the micrometer-scale defects, such as cracks and wrinkles, and atomic-scale domain boundaries were apparent as nonuniform Joule heating on polycrystalline and epitaxially grown graphene. The present results indicate that LIT can serve as a fast and effective method of evaluating the quality and uniformity of large graphene films for device applications.

Growth of large-area atomically thin MoS_2 film via ambient pressure chemical vapor deposition

2015 ◽  
Vol 3 (4) ◽  
pp. 110 ◽  
Author(s):  
Caiyun Chen ◽  
Hong Qiao ◽  
Yunzhou Xue ◽  
Wenzhi Yu ◽  
Jingchao Song ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Ambient Pressure ◽  
Chemical Vapor ◽  
Large Area ◽  
Pressure Chemical

Two-dimensional model of a large area, inductively coupled, rectangular plasma source for chemical vapor deposition

1999 ◽  
Vol 27 (5) ◽  
pp. 1317-1328 ◽  
Author(s):  
J.L. Giuliani ◽  
V.A. Shamamian ◽  
R.E. Thomas ◽  
J.P. Apruzese ◽  
M. Mulbrandon ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Plasma Source ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Large Area ◽  
Inductively Coupled ◽  
Two Dimensional Model
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