Impact of post-growth thermal annealing and environmental exposure on the unintentional doping of CVD graphene films

2012 ◽  
Vol 30 (4) ◽  
pp. 041213 ◽  
Author(s):  
Hossein Sojoudi ◽  
Jose Baltazar ◽  
Clifford Henderson ◽  
Samuel Graham
Keyword(s):  
Thermal Annealing ◽  
Environmental Exposure ◽  
Cvd Graphene ◽  
Graphene Films ◽  
Unintentional Doping

scholarly journals IMPROVING THE SHEET RESISTANCE OF CVD-GRAPHENE FILMS VIA DOPING

2018 ◽  
pp. 1-1 ◽  
Author(s):  
Gülsüm Ersü ◽  
Fethullah Güneş ◽  
Ahmet Aykaç ◽  
Mustafa Can
Keyword(s):  
Sheet Resistance ◽  
Cvd Graphene ◽  
Graphene Films

The formation mechanism of hexagonal Mo2C defects in CVD graphene grown on liquid copper

2020 ◽  
Vol 22 (4) ◽  
pp. 2176-2180 ◽  
Author(s):  
Maryam Saeed ◽  
Joseph D. Robson ◽  
Ian A. Kinloch ◽  
Brian Derby ◽  
Chun-Da Liao ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Molybdenum Carbide ◽  
Liquid Copper ◽  
Cvd Graphene ◽  
Graphene Films

Engineered defects in CVD graphene films are a challenge, and the growth of molybdenum carbide (Mo2C) with CVD graphene can hold great potential. The formation mechanism of Mo2C in CVD graphene is proposed.

scholarly journals Barrier Performance of CVD Graphene Films Using a Facile P3HT Thin Film Optical Transmission Test

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Srinivasa Kartik Nemani ◽  
Hossein Sojoudi
Keyword(s):  
Thin Film ◽  
Absorption Spectra ◽  
Optical Transmission ◽  
Screening Method ◽  
Ambient Conditions ◽  
Cvd Graphene ◽  
Barrier Materials ◽  
Graphene Films ◽  
Barrier Performance ◽  
Transmission Test

The barrier performance of CVD graphene films was determined using a poly(3-hexylthiophene) (P3HT) thin film optical transmission test. P3HT is a semiconducting polymer that photo-oxidatively degrades upon exposure to oxygen and light. The polymer is stable under ambient conditions and indoor lighting, enabling P3HT films to be deposited and encapsulated in air. P3HT’s stability under ambient conditions makes it desirable for an initial evaluation of barrier materials as a complimentary screening method in combination with conventional barrier tests. The P3HT test was used to demonstrate improved barrier performance for polymer substrates after addition of CVD graphene films. A layer-by-layer transfer method was utilized to enhance the barrier performance of monolayer graphene. Another set of absorption measurements were conducted to demonstrate the barrier performance of graphene and the degradation mechanism of graphene/P3HT over multiple wavelengths from 400 to 800 nm. The absorption spectra for graphene/polymer composite were simulated by solving Fresnel equations. The simulation results were found to be in good agreement with the measured absorption spectra. The P3HT degradation results qualitatively indicate the potential of graphene films as a possible candidate for medium performance barriers.

‘Bubble-Free’ Electrochemical Delamination of CVD Graphene Films

Small ◽  
2014 ◽  
Vol 11 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Christie Thomas Cherian ◽  
Francesco Giustiniano ◽  
Iñigo Martin-Fernandez ◽  
Henrik Andersen ◽  
Jayakumar Balakrishnan ◽  
...  
Keyword(s):  
Cvd Graphene ◽  
Graphene Films

scholarly journals Scalable ZnO nanotube arrays grown on CVD-graphene films

APL Materials ◽  
2016 ◽  
Vol 4 (10) ◽  
pp. 106104 ◽  
Author(s):  
J. B. Park ◽  
H. Oh ◽  
J. Park ◽  
N.-J. Kim ◽  
H. Yoon ◽  
...  
Keyword(s):  
Nanotube Arrays ◽  
Cvd Graphene ◽  
Zno Nanotube ◽  
Graphene Films

Monitoring the doping of graphene on SiO2/Si substrates during the thermal annealing process

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72859-72864 ◽  
Author(s):  
S. D. Costa ◽  
J. Ek Weis ◽  
O. Frank ◽  
M. Fridrichová ◽  
M. Kalbac
Keyword(s):  
Thermal Annealing ◽  
Annealing Process ◽  
Raman Peak ◽  
Cvd Graphene ◽  
Si Substrates ◽  
Thermal Annealing Process ◽  
Compression Level

It is the temperature of annealing after the transfer of CVD graphene influencing the doping and compression level, and thus the various Raman peak positions reported in the literature.

scholarly journals Flexible and monolithically integrated multicolor light emitting diodes using morphology-controlled GaN microstructures grown on graphene films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Keundong Lee ◽  
Dongha Yoo ◽  
Hongseok Oh ◽  
Gyu-Chul Yi
Keyword(s):  
Mechanical Stability ◽  
Growth Parameters ◽  
Light Emitting Diode ◽  
Growth Time ◽  
Controlled Growth ◽  
Light Emitting ◽  
Cvd Graphene ◽  
Monolithically Integrated ◽  
Graphene Films ◽  
Led Arrays

AbstractWe report flexible and monolithically integrated multicolor light-emitting diode (LED) arrays using morphology-controlled growth of GaN microstructures on chemical-vapor-deposited (CVD) graphene films. As the morphology-controlled growth template of GaN microstructures, we used position-controlled ZnO nanostructure arrays with different spacings grown on graphene substrates. In particular, we investigated the effect of the growth parameters, including micropattern spacings and growth time and temperature, on the morphology of the GaN microstructures when they were coated on ZnO nanostructures on graphene substrates. By optimizing the growth parameters, both GaN microrods and micropyramids formed simultaneously on the graphene substrates. Subsequent depositions of InGaN/GaN quantum well and p-GaN layers and n- and p-type metallization yielded monolithic integration of microstructural LED arrays on the same substrate, which enabled multicolor emission depending on the shape of the microstructures. Furthermore, the CVD graphene substrates beneath the microstructure LEDs facilitated transfer of the LED arrays onto any foreign substrate. In this study, Cu foil was used for flexible LEDs. The flexible devices exhibited stable electroluminescence, even under severe bending conditions. Cyclic bending tests demonstrated the excellent mechanical stability and reliability of the devices.

Controlled synthesis of few layer graphene films for gas sensor applications

2015 ◽  
Vol 1786 ◽  
pp. 65-70
Author(s):  
S. Chaudhari ◽  
A.R. Graves ◽  
M.V. Cain ◽  
C.D. Stinespring
Keyword(s):  
Raman Spectroscopy ◽  
Gas Sensor ◽  
Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Defect Density ◽  
Electrical Characterization ◽  
Layer Graphene ◽  
Graphene Films ◽  
Few Layer Graphene

ABSTRACTA novel approach for synthesis of few layer graphene films on SiC has been developed which uses halogen based inductively coupled-reactive ion etching (ICP-RIE) and rapid thermal annealing (RTA) in atmospheric pressure argon. These films have been characterized using x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Surface characterization by XPS reveals the presence of defects similar to those observed for graphene oxide (GO) but at a much lower levels that those observed for GO. As in the case for GO, the defect density could be further reduced by chemical methods which improved carbon to defect ratio based on XPS analyses. Raman spectroscopy showed the presence of D, G and 2D peaks at 1330 cm-1, 1599 cm-1 and 2671 cm-1, respectively, which is comparable with similar graphene films formed by thermal annealing of SiC. The full widths at half max (FWHM) for these peaks was, however, comparable to those observed for GO. Electrical characterization of these graphene films using collinear four point probe measurements showed the electrical resistivity of these films is consistent with the observed values for few layer exfoliated graphene. Gas sensor structures were fabricated using lithography free methods, and initial gas response studies were performed for H2.

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