Characterization of High Quality, Large-Scale Growth of Monolayer WS2 Domains via Chemical Vapor Deposition Technique

2021 ◽  
Author(s):  
Somayeh Asgary ◽  
Amir Hoshang Ramezani ◽  
Zhaleh Ebrahimi Nejad
Keyword(s):  
Large Scale ◽  
Average Length ◽  
Chemical Vapor ◽  
Growth Time ◽  
High Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Regular Triangle ◽  
Vapor Deposition Technique

Abstract WS2 flakes have been grown successfully on SiO2 substrate via chemical vapor (CVD) deposition method by reduction and sulfurization of WO3 using Ar/ H2 gas and sulfur evaporated from solid sulfur powder. The prepared samples were characterized by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). Large domain WS2 monolayers are obtained by extending the growth time. The perfect triangular single-crystalline WS2 flakes with an average length of more than 35 µm were achieved. The sharp PL peak (∼1.98 eV) and two distinct Raman peaks (E2g and A1g) with a ∼ 71.5 cm-1 peak split indicating that relatively high quality WS2 crystals with a regular triangle shape can be synthesized. Higher growth time shows larger triangular-shaped of WS2.

Growth of GaN epilayers on Si(111) substrates using multiple buffer layers

2001 ◽  
Vol 693 ◽  
Author(s):  
P.R. Hageman ◽  
S. Haffouz ◽  
A. Grzegorczk ◽  
V. Kirilyuk ◽  
P.K. Larsen
Keyword(s):  
Atomic Force Microscopy ◽  
Epitaxial Films ◽  
Buffer Layers ◽  
High Quality ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Vapor Deposition Technique

AbstractWe present a study of the growth of high quality GaN films on Si(111) substrates by MetalOrganic Chemical Vapor Deposition technique. In order to improve the quality of the epitaxial films we introduced different nucleation or buffer layers and combinations of them. Our results obtained on an optimized AlN nucleation layer will serve as reference point. In order to improve the quality of the epitaxial films we introduced different combinations of nucleation and intermediate layers. The first combination consists of an optimized AlN nucleation layer followed by a 1 m-thick GaN film, on which we deposited SixNy/GaN intermediate layers. Based on the optimized AlN nucleation layer, we introduced AlGaN/GaN superlattices or AlN intermediate buffer layers. Additionally, we present results on the modification the Si(111) surface with NH3 to promote nucleation from selective GaN islands. In all experiments the total thickness of the GaN epilayers was 3 m m. X-ray diffraction, photoluminescence, Hall measurements and atomic force microscopy were used in order to elucidate the effectiveness of these growth processes. For the most successful deposition scheme, the one with the SixNy/GaN intermediate layers, the resulting GaN layers are of high quality as compared to the other methods. The donor bound exciton, which dominates the photoluminescence spectrum, showed a full width at half maximum (FWHM) of about 50 meV at room temperature and 10 meV at 4K. The FWHM of the symmetric (0002) rocking curves in w-scan is about 640 arcsec. The root-mean-square roughness, as measured by atomic force microscopy, does not exceed 10 Å.

Fabrication and Characterization of High Quality Micro Diamonds by Hot Filament CVD

2011 ◽  
Vol 325 ◽  
pp. 582-587
Author(s):  
T. Zhang ◽  
Fang Hong Sun ◽  
Bin Shen ◽  
Z.M. Zhang
Keyword(s):  
Silicon Wafer ◽  
Chemical Vapor ◽  
High Quality ◽  
Acetone Concentration ◽  
Vapor Deposition Technique ◽  
Hot Filament Cvd ◽  
Average Size ◽  
Hot Filament

The high quality micro diamonds with the euhedral diamond faces are fabricated by hot filament chemical vapor deposition technique (HFCVD). The high pressure and high temperature (HPHT) single crystal diamonds in size of 1 μm are used as seeds. In order to disperse the diamond seeds uniformly on a silicon wafer, the photoresist solution with diamond seeds are performed on the silicon wafer by a spin coater machine. The high substrate temperature and low acetone concentration are employed for decreasing the nucleation rate and accelerating the growth rate. The morphology and quality of the micro diamonds are observed and analyzed by SEM and Raman spectroscopy. After 4 hours of the deposition, the surface imperfections of the diamond seeds have disappeared completely, and the euhedral diamond faces with (111) and (100) begin to emerge. Subsequently, 8 hours of deposition leads to a final average size of approximately 4 μm. The micro diamonds have very high quality, and the surfaces appear flat and smooth in this stage. The results indicate that it is an effective way to eliminate the defects of the HPHT micro diamonds and develop high quality diamonds with well-defined morphology by HFCVD technique.

Low Temperature Growth of CVD Nanocrystalline Diamond Thin Film by Designed SWP-CVD with Various Working Pressures

2019 ◽  
Vol 11 (9) ◽  
pp. 1292-1297
Author(s):  
Yeong Min Park ◽  
Moon Ki Han ◽  
Mun Ki Bae ◽  
Tae Gyu Kim
Keyword(s):  
Microwave Plasma ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Slot Antenna ◽  
High Quality ◽  
Plasma Chemical Vapor Deposition ◽  
Force Microscopy ◽  
Diamond Thin Film ◽  
Atomic Force

Nanocrystalline diamond (NCD) is exceptionally useful for a variety of applications and is of significant interest to researchers in technological and scientific fields due to its excellent mechanical and chemical properties, such as its hardness and high thermal conductivity. We have modified a microwave plasma chemical vapor deposition (MPCVD; Astex Inc.) system with a slot antenna designed for surface wave plasma (SWP) and successfully fabricated high quality thin NCD film. This SWP-CVD process fabricates high quality diamond film at 300 °C, while a normal MPCVD process requires the temperature of the substrate to be above 800 °C. We studied the fabricated NCD samples in detail, measuring their surface morphology by field emission scanning electron microscopy (FESEM); their structural-chemical properties by Raman spectroscopy; and their surface roughness by atomic force microscopy (AFM).

Deposition of GaN Films on Freestanding CVD Thick Diamond Films

2010 ◽  
Vol 654-656 ◽  
pp. 1740-1743 ◽  
Author(s):  
Dong Zhang ◽  
Yi Zhen Bai ◽  
Fu Wen Qin ◽  
Ji Ming Bian
Keyword(s):  
Electron Cyclotron Resonance ◽  
Diamond Films ◽  
Chemical Vapor ◽  
High Energy ◽  
Organic Chemical ◽  
High Quality ◽  
Small Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic

High quality GaN films are deposited on freestanding thick diamond films by electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD). The characteristics of GaN films were investigated by x-ray diffraction analysis (XRD), reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM). The high quality GaN films with small surface roughness of 8.3 nm and high c-orientation are successfully achieved at the optimized nitriding time with the diamond substrate. These properties of GaN films with small surface smoothness and high c-orientation are well used as piezoelectric films for surface acoustic wave (SAW) devices.

scholarly journals Epitaxial Growth of III-Nitride Layers on Aluminum Nitride Substrates

1999 ◽  
Vol 4 (S1) ◽  
pp. 411-416 ◽  
Author(s):  
L.J. Schowalter ◽  
Y. Shusterman ◽  
R. Wang ◽  
I. Bhat ◽  
G. Arunmozhi ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Electrical Characterization ◽  
High Quality ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Image Position ◽  
Nitride Layers ◽  
Very High

High quality, epitaxial growth of AlN and AlxGa1−xN by OMVPE has been demonstrated on single-crystal AlN substrates. Here we report characterization of epitaxial layers on an a-face AlN substrate using Rutherford Backscattering/ion channeling, atomic force microscopy (AFM), x-ray rocking curves, and preliminary electrical characterization. Ion channeling along the [100] axis gives a channeling minimum yield of 1.5% indicating a very high quality epitaxial layer.

Epitaxial Growth of III-Nitride Layers on Aluminum Nitride Substrates

1998 ◽  
Vol 537 ◽  
Author(s):  
L.J. Schowalter ◽  
Y. Shusterman ◽  
R. Wang ◽  
I. Bhat ◽  
G. Arunmozhi ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Electrical Characterization ◽  
High Quality ◽  
X Ray ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Nitride Layers ◽  
Very High

AbstractHigh quality, epitaxial growth of AlN and AlxGal-xN by OMVPE has been demonstrated on single-crystal AIN substrates. Here we report characterization of epitaxial layers on an a-face AlN substrate using Rutherford Backscattering/ion channeling, atomic force microscopy (AFM), x-ray rocking curves, and preliminary electrical characterization. Ion channeling along the [1010] axis gives a channeling minimum yield of 1.5% indicating a very high quality epitaxial layer.

scholarly journals Growth of High-Quality GaN Films on Epitaxial AlN/Sapphire Templates

2019 ◽  
Author(s):  
Xiejia
Keyword(s):  
Chemical Vapor ◽  
Organic Chemical ◽  
High Quality ◽  
Rocking Curve ◽  
Force Microscopy ◽  
Atomic Force ◽  
Low Dislocation Density ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Microscopy Images

High quality GaN films have been successfully grown on multi-AlN/sapphire templates by metal organic chemical vapor deposition system. The Hall mobility and the carrier concentration of 720 cm2/Vs and 6.7x1016 cm-3 at 300K, respectively, along with low dislocation density of 4.1x109 cm-2 have been achieved. The X-ray rocking curve full-width at half-maximum were 160 and 290 arcsec for (0004) and (20-24) reflection planes also obtained, respectively. Besides that, the atomic force microscopy images showed smooth surface morphology and a higher intensity near the band edge was also observed by photoluminescence measurement result.

Influence of TMGa Flux on the Improvement of GaN Films on Thick Freestanding Diamond Films

2013 ◽  
Vol 475-476 ◽  
pp. 1299-1302
Author(s):  
Shan Lin Cui ◽  
Hong Gang ◽  
Zheng Nian Li
Keyword(s):  
Electron Cyclotron Resonance ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
High Quality ◽  
Small Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
Trimethyl Gallium

High-quality GaN films are deposited on diamond films using an electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD) under the condition of the proper Trimethyl gallium (TMGa) flux. The influence of TMGa flux on the properties of GaN films is systematically investigated by x-ray diffraction analysis (XRD) and atomic force microscopy (AFM). The results show that the high quality GaN films with small surface roughness and high c-orientation are successfully achieved at the optimized flux. The most significant improvements in morphological and structural properties of GaN films are obtained by using a proper TMGa flux

scholarly journals Thermal decomposition and chemical vapor deposition: a comparative study of multi-layer growth of graphene on SiC(000-1)

MRS Advances ◽  
2016 ◽  
Vol 1 (55) ◽  
pp. 3667-3672 ◽  
Author(s):  
D. Convertino ◽  
A. Rossi ◽  
V. Miseikis ◽  
V. Piazza ◽  
C. Coletti
Keyword(s):  
Thermal Decomposition ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Large Scale ◽  
Chemical Vapor ◽  
Layer Growth ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
Grown Graphene

ABSTRACTThis work presents a comparison of the structural, chemical and electronic properties of multi-layer graphene grown on SiC(000-1) by using two different growth approaches: thermal decomposition and chemical vapor deposition (CVD). The topography of the samples was investigated by using atomic force microscopy (AFM), and scanning electron microscopy (SEM) was performed to examine the sample on a large scale. Raman spectroscopy was used to assess the crystallinity and electronic behavior of the multi-layer graphene and to estimate its thickness in a non-invasive way. While the crystallinity of the samples obtained with the two different approaches is comparable, our results indicate that the CVD method allows for a better thickness control of the grown graphene.

Growth and Characterization of Organic Polymeric Thin Films From Isopropanol by PECVD.

2009 ◽  
Vol 1242 ◽  
Author(s):  
J. O. Martínez-Gutiérrez ◽  
G. Romero-Paredes ◽  
R. Peña-Sierra ◽  
A. Ávila-García ◽  
G. Juárez-Díaz
Keyword(s):  
Thin Films ◽  
Visible Region ◽  
Chemical Vapor ◽  
Ammonium Hydroxide ◽  
Organic Thin Films ◽  
Optical Bandgap ◽  
Polymeric Thin Films ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTPolymerized organic thin films were synthesized on a variety of substrates by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique using isopropanol as precursor. Hydrogen peroxide, ammonium hydroxide, and iodine dissolved in isopropanol were used as dopants and chlorobenzene as copolymerization precursor. The structural, optical and electrical properties of the films were studied as functions of the dopant type and concentration.The polymeric films were characterized by variable angle ellipsometry (VAE), atomic force microscopy (AFM), Fourier Transform Infrared spectroscopy (FTIR), ultraviolet-visible transmission spectroscopy and photoluminescence. The electrical film behavior was explored by the four points probe method.The growth rate, refractive index, optical bandgap, chemical structure and resistivity of the films strongly depend on the concentration and type of dopant added. The AFM microphotographs showed smooth surfaces with RMS roughness less than 10 nm. The optical bandgap values of the films were in the range of 2.6 to 3.26 eV, the resistivity was in the order of 103 – 104 ohm-cm. The photoluminescence response of the polymerized films was obtained in the visible region, by exciting with a UV laser.

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