scholarly journals Ultrafast Growth of Uniform Multi-Layer Graphene Films Directly on Silicon Dioxide Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 964 ◽  
Author(s):  
Lijie Zhou ◽  
Shuai Wei ◽  
Chuanyang Ge ◽  
Chao Zhao ◽  
Bin Guo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Silicon Dioxide ◽  
Large Scale ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Poor Quality ◽  
Industrial Applications ◽  
Si Substrate ◽  
Dielectric Substrates

To realize the applications of graphene in electronics, a large-scale, high-quality, and uniform graphene film should first be placed on the dielectric substrates. Challenges still remain with respect to the current methods for the synthesis graphene directly on the dielectric substrates via chemical vapor deposition, such as a low growth rate and poor quality. Herein, we present an ultrafast method for direct growth of uniform graphene on a silicon dioxide (SiO2/Si) substrate using methanol as the only carbon source. A 1 × 1 cm2 SiO2/Si substrate square was almost fully covered with graphene within 5 min, resulting in a record growth rate of ~33.6 µm/s. This outcome is attributed to the quick pyrolysis of methanol, with the help of trace copper atoms. The as-grown graphene exhibited a highly uniform thickness, with a sheet resistance of 0.9–1.2 kΩ/sq and a hole mobility of up to 115.4 cm2/V·s in air at room temperature. It would be quite suitable for transparent conductive electrodes in electrophoretic displays and may be interesting for related industrial applications.

scholarly journals Research on the Preparation and Spectral Characteristics of Graphene/TMDs Hetero-structures

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Tao Han ◽  
Hongxia Liu ◽  
Shulong Wang ◽  
Shupeng Chen ◽  
Kun Yang
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Spectral Characteristics ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Si Substrate ◽  
Broadband Absorption ◽  
Gate Effect ◽  
Pressure Chemical

AbstractThe Van der Waals (vdWs) hetero-structures consist of two-dimensional materials have received extensive attention, which is due to its attractive electrical and optoelectronic properties. In this paper, the high-quality large-size graphene film was first prepared by the chemical vapor deposition (CVD) method; then, graphene film was transferred to SiO2/Si substrate; next, the graphene/WS2 and graphene/MoS2 hetero-structures were prepared by the atmospheric pressure chemical vapor deposition method, which can be achieved by directly growing WS2 and MoS2 material on graphene/SiO2/Si substrate. Finally, the test characterization of graphene/TMDs hetero-structures was performed by AFM, SEM, EDX, Raman and PL spectroscopy to obtain and grasp the morphology and luminescence laws. The test results show that graphene/TMDs vdWs hetero-structures have the very excellent film quality and spectral characteristics. There is the built-in electric field at the interface of graphene/TMDs heterojunction, which can lead to the effective separation of photo-generated electron–hole pairs. Monolayer WS2 and MoS2 material have the strong broadband absorption capabilities, the photo-generated electrons from WS2 can transfer to the underlying p-type graphene when graphene/WS2 hetero-structures material is exposed to the light, and the remaining holes can induced the light gate effect, which is contrast to the ordinary semiconductor photoconductors. The research on spectral characteristics of graphene/TMDs hetero-structures can pave the way for the application of novel optoelectronic devices.

scholarly journals Computational synthesis of 2D materials grown by chemical vapor deposition

2021 ◽  
Author(s):  
Kasra Momeni ◽  
Yanzhou Ji ◽  
Long-Qing Chen
Keyword(s):  
Chemical Vapor Deposition ◽  
Flexible Electronics ◽  
Vapor Deposition ◽  
Large Scale ◽  
Growth Parameters ◽  
2D Materials ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Major Barrier ◽  
Cvd Growth

Abstract The exotic properties of 2D materials made them ideal candidates for applications in quantum computing, flexible electronics, and energy technologies. A major barrier to their adaptation for industrial applications is their controllable and reproducible growth at a large scale. A significant effort has been devoted to the chemical vapor deposition (CVD) growth of wafer-scale highly crystalline monolayer materials through exhaustive trial-and-error experimentations. However, major challenges remain as the final morphology and growth quality of the 2D materials may significantly change upon subtle variation in growth conditions. Here, we introduced a multiscale/multiphysics model based on coupling continuum fluid mechanics and phase-field models for CVD growth of 2D materials. It connects the macroscale experimentally controllable parameters, such as inlet velocity and temperature, and mesoscale growth parameters such as surface diffusion and deposition rates, to morphology of the as-grown 2D materials. We considered WSe2 as our model material and established a relationship between the macroscale growth parameters and the growth coverage. Our model can guide the CVD growth of monolayer materials and paves the way to their synthesis-by-design. Graphic abstract

Direct Growth of Graphene on SiO2 by Using Ga-Ni Flux

2013 ◽  
Vol 477-478 ◽  
pp. 1242-1245
Author(s):  
Qiang Yu ◽  
Jing Cun Zhang ◽  
Bing Cao ◽  
Shun Yu He ◽  
Chin Hua Wang ◽  
...  
Keyword(s):  
Sacrificial Layer ◽  
Carbon Film ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Force Microscopy ◽  
Dielectric Substrates ◽  
Atomic Force ◽  
Growth Method ◽  
Direct Growth

A new growth method of graphene directly on the bare dielectric substrates by CVD (Chemical Vapor Deposition) method with Ga-Ni flux as sacrificial layer is reported in this work. Ga-Ni flux acts as not only a container to store carbon atoms which are dissolved from amourphous carbon film when heated, but also as a catalyst to promote the formation of graphene when cooled. In the process of growth, the Ga-Ni flux dewets and evaporates during the rearrangement of carbon atoms, resulting in graphene synthesized directly on the bare dielectric substrates. Scanning Raman Mapping and Spectroscopy, Scanning Electron Microscopy, and Atomic Force Microscopy were adopted to characterize the graphene film.

Simulation of Surface Chemistry in CVD Technologies: A Detailed Deposition Model With Surface Diffusion

2010 ◽  
Author(s):  
Sergei Klimovich ◽  
Yuriy Gorbachev ◽  
Valeria Krzhizhanovskaya
Keyword(s):  
Large Scale ◽  
Chemical Vapor ◽  
Industrial Applications ◽  
Semiconductor Film ◽  
Flat Panel Displays ◽  
Plasma Chemical ◽  
Multiphysics Simulations ◽  
Spatial Uniformity ◽  
Key Issues ◽  
Deposition Processes

Modern electronics relies on high quality semiconductor materials. For thin films used in solar cells and flat panel displays, the key issues are the precise composition and spatial uniformity. Modeling and simulation are indispensable for optimizing the technologies of semiconductor film production, such as chemical vapor deposition (CVD), plasma enhanced CVD and hot-wire CVD. Multiphysics simulations of electromagnetic dynamics coupled with the flow of reacting gases, plasma discharge and deposition processes, allowed us to optimize large-scale plasma chemical reactors [1] and to find other solutions to complex industrial applications [2,3].

scholarly journals SYNTHETIC GRAPHENE GROWN BY CHEMICAL VAPOR DEPOSITION ON COPPER FOILS

2013 ◽  
Vol 27 (10) ◽  
pp. 1341002 ◽  
Author(s):  
TING FUNG CHUNG ◽  
TIAN SHEN ◽  
HELIN CAO ◽  
LUIS A. JAUREGUI ◽  
WEI WU ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Large Scale ◽  
Rapid Development ◽  
Graphene Film ◽  
Single Layer ◽  
Chemical Vapor ◽  
Mechanical And Thermal Properties ◽  
Large Area ◽  
Exfoliated Graphene

The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interest. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapor deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this paper, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapor deposition. We also discuss potential applications of such large-scale synthetic graphene.

scholarly journals Unusual Dependence of the Diamond Growth Rate on the Methane Concentration in the Hot Filament Chemical Vapor Deposition Process

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 426
Author(s):  
Byeong-Kwan Song ◽  
Hwan-Young Kim ◽  
Kun-Su Kim ◽  
Jeong-Woo Yang ◽  
Nong-Moon Hwang
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Methane Concentration ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Lower Growth ◽  
Filament Temperature ◽  
Diamond Phase ◽  
Hot Filament

Although the growth rate of diamond increased with increasing methane concentration at the filament temperature of 2100 °C during a hot filament chemical vapor deposition (HFCVD), it decreased with increasing methane concentration from 1% CH4 –99% H2 to 3% CH4 –97% H2 at 1900 °C. We investigated this unusual dependence of the growth rate on the methane concentration, which might give insight into the growth mechanism of a diamond. One possibility would be that the high methane concentration increases the non-diamond phase, which is then etched faster by atomic hydrogen, resulting in a decrease in the growth rate with increasing methane concentration. At 3% CH4 –97% H2, the graphite was coated on the hot filament both at 1900 °C and 2100 °C. The graphite coating on the filament decreased the number of electrons emitted from the hot filament. The electron emission at 3% CH4 –97% H2 was 13 times less than that at 1% CH4 –99% H2 at the filament temperature of 1900 °C. The lower number of electrons at 3% CH4 –97% H2 was attributed to the formation of the non-diamond phase, which etched faster than diamond, resulting in a lower growth rate.

scholarly journals Large-Scale Precipitation Variability over Northwest China Inferred from Tree Rings

2011 ◽  
Vol 24 (13) ◽  
pp. 3457-3468 ◽  
Author(s):  
Keyan Fang ◽  
Xiaohua Gou ◽  
Fahu Chen ◽  
Edward Cook ◽  
Jinbao Li ◽  
...  
Keyword(s):  
Tree Ring ◽  
Large Scale ◽  
Principal Component ◽  
Northwest China ◽  
Poor Quality ◽  
Contour Method ◽  
Precipitation Reconstruction ◽  
Nw China ◽  
Climate Station ◽  
Instrumental Records

Abstract A preliminary study of a point-by-point spatial precipitation reconstruction for northwestern (NW) China is explored, based on a tree-ring network of 132 chronologies. Precipitation variations during the past ~200–400 yr (the common reconstruction period is from 1802 to 1990) are reconstructed for 26 stations in NW China from a nationwide 160-station dataset. The authors introduce a “search spatial correlation contour” method to locate candidate tree-ring predictors for the reconstruction data of a given climate station. Calibration and verification results indicate that most precipitation reconstruction models are acceptable, except for a few reconstructions (stations Hetian, Hami, Jiuquan, and Wuwei) with degraded quality. Additionally, the authors compare four spatial precipitation factors in the instrumental records and reconstructions derived from a rotated principal component analysis (RPCA). The northern and southern Xinjiang factors from the instrumental and reconstructed data agree well with each other. However, differences in spatial patterns between the instrumentation and reconstruction data are also found for the other two factors, which probably result from the relatively poor quality of a few stations. Major drought events documented in previous studies—for example, from the 1920s through the 1930s for the eastern part of NW China—are reconstructed in this study.

scholarly journals Blackbody-sensitive room-temperature infrared photodetectors based on low-dimensional tellurium grown by chemical vapor deposition

2021 ◽  
Vol 7 (16) ◽  
pp. eabf7358
Author(s):  
Meng Peng ◽  
Runzhang Xie ◽  
Zhen Wang ◽  
Peng Wang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Spectral Response ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Infrared Detection ◽  
Infrared Photodetectors ◽  
Bandgap Semiconductors ◽  
Low Dimensional

Blackbody-sensitive room-temperature infrared detection is a notable development direction for future low-dimensional infrared photodetectors. However, because of the limitations of responsivity and spectral response range for low-dimensional narrow bandgap semiconductors, few low-dimensional infrared photodetectors exhibit blackbody sensitivity. Here, highly crystalline tellurium (Te) nanowires and two-dimensional nanosheets were synthesized by using chemical vapor deposition. The low-dimensional Te shows high hole mobility and broadband detection. The blackbody-sensitive infrared detection of Te devices was demonstrated. A high responsivity of 6650 A W−1 (at 1550-nm laser) and the blackbody responsivity of 5.19 A W−1 were achieved. High-resolution imaging based on Te photodetectors was successfully obtained. All the results suggest that the chemical vapor deposition–grown low-dimensional Te is one of the competitive candidates for sensitive focal-plane-array infrared photodetectors at room temperature.

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