scholarly journals Flexibility of Fluorinated Graphene-Based Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1032 ◽  
Author(s):  
Irina Antonova ◽  
Nadezhda Nebogatikova ◽  
Nabila Zerrouki ◽  
Irina Kurkina ◽  
Artem Ivanov
Keyword(s):  
Chemical Vapor Deposition ◽  
Polyvinyl Alcohol ◽  
Vapor Deposition ◽  
Tensile Strain ◽  
Flexible Substrate ◽  
Chemical Vapor ◽  
Multilayer Graphene ◽  
Current Ratio ◽  
Bending Radius ◽  
Fluorinated Graphene

The resistivity of different films and structures containing fluorinated graphene (FG) flakes and chemical vapor deposition (CVD)-grown graphene of various fluorination degrees under tensile and compressive strains due to bending deformations was studied. Graphene and multilayer graphene films grown by means of the chemical vapor deposition (CVD) method were transferred onto the flexible substrate by laminating and were subjected to fluorination. They demonstrated a weak fluorination degree (F/C lower 20%). Compressive strains led to a strong (one-two orders of magnitude) decrease in the resistivity in both cases, which was most likely connected with the formation of additional conductive paths through fluorinated graphene. Tensile strain up to 3% caused by the bending of both types of CVD-grown FG led to a constant value of the resistivity or to an irreversible increase in the resistivity under repeated strain cycles. FG films created from the suspension of the fluorinated graphene with a fluorination degree of 20–25%, after the exclusion of design details of the used structures, demonstrated a stable resistivity at least up to 2–3% of tensile and compressive strain. The scale of resistance changes ΔR/R0 was found to be in the range of 14–28% with a different sign at the 10% tensile strain (bending radius 1 mm). In the case of the structures with the FG thin film printed on polyvinyl alcohol, a stable bipolar resistive switching was observed up to 6.5% of the tensile strain (bending radius was 2 mm). A further increase in strain (6.5–8%) leads to a decrease in ON/OFF current ratio from 5 down to 2 orders of magnitude. The current ratio decrease is connected with an increase under the tensile strain in distances between conductive agents (graphene islands and traps at the interface with polyvinyl alcohol) and thickness of fluorinated barriers within the active layer. The excellent performance of the crossbar memristor structures under tensile strain shows that the FG films and structures created from suspension are especially promising for flexible electronics.

scholarly journals Low-Temperature Chemical Vapor Deposition Growth of MoS2 Nanodots and Their Raman and Photoluminescence Profiles

2021 ◽  
Vol 3 ◽  
Author(s):  
Larionette P. L. Mawlong ◽  
Ravi K. Biroju ◽  
P. K. Giri
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Substrate Temperature ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Flexible Substrate ◽  
Chemical Vapor ◽  
Structural Defects ◽  
Chemical Vapor Deposition Growth ◽  
Raman Modes

We report on the growth of an ordered array of MoS2 nanodots (lateral sizes in the range of ∼100–250 nm) by a thermal chemical vapor deposition (CVD) method directly onto SiO2 substrates at a relatively low substrate temperature (510–560°C). The temperature-dependent growth and evolution of MoS2 nanodots and the local environment of sulfur-induced structural defects and impurities were systematically investigated by field emission scanning electron microscopy, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. At the substrate temperature of 560°C, we observed mostly few-layer MoS2, and at 510°C, multilayer MoS2 growth, as confirmed from the Raman line shape analysis. With reduced substrate temperature, the density of MoS2 nanodots decreases, and layer thickness increases. Raman studies show characteristic Raman modes of the crystalline MoS2 layer, along with two new Raman modes centered at ∼346 and ∼361 cm−1, which are associated with MoO2 and MoO3 phases, respectively. Room temperature photoluminescence (PL) studies revealed strong visible PL from MoS2 layers, which is strongly blue-shifted from the bulk MoS2 flakes. The strong visible emission centered at ∼ 658 nm signifies a free excitonic transition in the direct gap of single-layer MoS2. Position-dependent PL profiles show excellent uniformity of the MoS2 layers for samples grown at 540 and 560°C. These results are significant for the low-temperature CVD growth of a few-layer MoS2 dots with direct bandgap photoluminescence on a flexible substrate.

Single and Few-Layer MoS2: CVD Synthesis, Transference, and Photodetection Application

MRS Advances ◽  
2017 ◽  
Vol 2 (60) ◽  
pp. 3709-3714
Author(s):  
Gustavo A. Saenz ◽  
Carlos de Anda Orea ◽  
Anupama B. Kaul
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Flexible Substrate ◽  
Synthesis Method ◽  
Chemical Vapor ◽  
Synthesis Methods ◽  
Phase Reaction ◽  
Isolation And Characterization ◽  
Cvd Synthesis

ABSTRACTTwo-dimensional layered materials, materials with weak out-of-plane van der Waals bonding and strong in-plane covalent bonding, have attracted special attention in recent years since the isolation and characterization of monolayer graphite, the graphene. The electrical bandgap in Transition Metal Di-Chalcogenides (TMDCs), non-existent in graphene, make them a good alternative family of materials for novel electronic and optoelectronic applications. 2H- MoS2, one of the most stable TMDCs, has been extensively studied, including the synthesis methods, and its potential applications in photodetection. The chemical vapor deposition (CVD) synthesis method has increased its potential over the years. The advantages of this method are scalability compared to micromechanical exfoliation, common process used in research laboratories, and the maintenance of the quality and intrinsic properties of the material compared to the liquid exfoliation methods. In this work, we synthesized high quality pristine 2H-MoS2 via atmospheric pressure chemical vapor deposition (APCVD) by vapor phase reaction of MoO3 and S powder precursors. The samples were characterized via Raman and photoluminescence (PL) spectroscopy and compared to mechanically exfoliated MoS2 crystal by measuring the full-width half maxima (FWHM) of monolayer and few-layer mesoscopic flakes. In addition, the CVD synthesized single and few-layered MoS2 domains were transferred to different substrates using a high yield process, including a flexible substrate, preserving the quality of the material. Finally, and mechanically exfoliated MoS2 two-terminal photodetector was designed, fabricated, and measured. Demonstrating thus the capability of heterostructure fabrication and the quality of our synthesis and device fabrication process.

Insights into graphene wettability transparency by locally probing its surface free energy

Nanoscale ◽  
2019 ◽  
Vol 11 (16) ◽  
pp. 7944-7951 ◽  
Author(s):  
Jin-You Lu ◽  
Tuza Olukan ◽  
Srinivasa Reddy Tamalampudi ◽  
Abdulrahman Al-Hagri ◽  
Chia-Yun Lai ◽  
...  
Keyword(s):  
Free Energy ◽  
Chemical Vapor Deposition ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Multilayer Graphene ◽  
Natural Graphite

In this work, we study the surface energy of monolayer, bilayer and multilayer graphene coatings, produced through exfoliation of natural graphite flakes and chemical vapor deposition.

scholarly journals AB-Stacked Multilayer Graphene Synthesized via Chemical Vapor Deposition: A Characterization by Hot Carrier Transport

ACS Nano ◽  
2012 ◽  
Vol 6 (2) ◽  
pp. 1142-1148 ◽  
Author(s):  
Carlos Diaz-Pinto ◽  
Debtanu De ◽  
Viktor G. Hadjiev ◽  
Haibing Peng
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Carrier Transport ◽  
Chemical Vapor ◽  
Multilayer Graphene ◽  
Hot Carrier

Multilayer-graphene-stabilized lithium deposition for anode-Free lithium-metal batteries

Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2710-2720 ◽  
Author(s):  
Addisu Alemayehu Assegie ◽  
Cheng-Chu Chung ◽  
Meng-Che Tsai ◽  
Wei-Nien Su ◽  
Chun-Wei Chen ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Multilayer Graphene ◽  
Lithium Metal ◽  
Lithium Metal Batteries ◽  
Lithium Deposition

Ultra-thin multilayer graphene film domain grown on Cu by chemical vapor deposition enables dendrite free lithium deposition in an anode-free Li metal battery via distributing localized current.

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