PMMA direct exfoliation for rapid and organic free transfer of centimeter-scale CVD graphene

2D Materials ◽  
2021 ◽  
Author(s):  
Hewei Zhao ◽  
Xianqin Xing ◽  
Gehui Zhang ◽  
Wenyu Liu ◽  
Haoyu Dong ◽  
...  
Keyword(s):  
Graphene Film ◽  
Chemical Vapor ◽  
Complete Removal ◽  
Large Area ◽  
Pmma Layer ◽  
Cvd Graphene ◽  
Higher Carrier Mobility ◽  
P Type ◽  
First Time ◽  
Incomplete Domains

Abstract Despite the various techniques developed for the transfer of large area graphene grown by chemical vapor deposition (CVD), the conventional PMMA transferring technique has been widely applied in laboratories due to its convenience and economical cost. However, the complete removal of PMMA on graphene surface has become a troublesome, and the PMMA residue could degrade the properties of graphene significantly. We report here a facile water assisted technique to directly peel off the PMMA layer over centimeter-sized CVD graphene film for the first time. No organic solvents are involved in the whole transfer process. The transferred graphene film is clean and intact over large area because of the cooperative effect of the capillary force and the van der Waals force which facilitates the conformal contact between graphene film and the substrate. Various types of graphene samples (i.e. monolayer, multilayer, and incomplete domains) can be easily transferred to diverse substrates including silicon wafer, sapphire, and quartz with good integrity. The transferred graphene film is of high cleanliness, and the graphene transistors show higher carrier mobility and lower level of p-type doping comparing to the conventional wet transfer technique.

HIGH FREQUENCY GRAPHENE TRANSISTORS USING LARGE-AREA CVD GRAPHENE AND ADVANCED DIELECTRICS

2011 ◽  
Vol 20 (03) ◽  
pp. 669-677
Author(s):  
OSAMA M. NAYFEH ◽  
TONY IVANOV ◽  
JAMES WILSON ◽  
ROBERT PROIE ◽  
MADAN DUBEY
Keyword(s):  
High Frequency ◽  
Gate Dielectric ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Monolayer Graphene ◽  
Large Area ◽  
Cvd Graphene ◽  
Ambipolar Behavior ◽  
Chemical Vapor Deposited ◽  
First Time

Graphene transistors using large area chemical-vapor-deposited (CVD) monolayer graphene and advanced dielectric stacks are constructed and examined. Top-gated devices with a SiO 2/ Al 2 O 3 gate-dielectric have a Dirac Point (DP) located at less than 5 V and asymmetric electron/hole mobility. In contrast, devices based on an advanced AlN interfacial layer have a DP located near 0V and a near symmetric carrier mobility- characteristics that could be more suitable for applications that require ambipolar behavior and low-power operation. For the first time, a measured RF cut-off frequency range of 1GHz is measured for top-gated transistors using CVD graphene. The results are of importance for the realization of graphene based, wafer-scale, high frequency electronics.

scholarly journals Correction: Controlled p-type substitutional doping in large-area monolayer WSe2 crystals grown by chemical vapor deposition

Nanoscale ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 365-365
Author(s):  
Sushil Kumar Pandey ◽  
Hussain Alsalman ◽  
Javad G. Azadani ◽  
Nezhueyotl Izquierdo ◽  
Tony Low ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Large Area ◽  
Substitutional Doping ◽  
P Type

Correction for ‘Controlled p-type substitutional doping in large-area monolayer WSe2 crystals grown by chemical vapor deposition’ by Stephen A. Campbell et al., Nanoscale, 2018, 10, 21374–21385.

Controlled p-type substitutional doping in large-area monolayer WSe2 crystals grown by chemical vapor deposition

Nanoscale ◽  
2018 ◽  
Vol 10 (45) ◽  
pp. 21374-21385 ◽  
Author(s):  
Sushil Kumar Pandey ◽  
Hussain Alsalman ◽  
Javad G. Azadani ◽  
Nezhueyotl Izquierdo ◽  
Tony Low ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Crystal Lattice ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Large Area ◽  
Tungsten Diselenide ◽  
2D Material ◽  
Substitutional Doping ◽  
P Type ◽  
Controlled Doping

Controlled doping of the p-type 2D material tungsten diselenide, done with niobium substitution for tungsten on the crystal lattice, can tune 2D transistor characteristics.

High-Efficiency, Thin-Film GaAs Solar Cells

1983 ◽  
Vol 105 (3) ◽  
pp. 237-242 ◽  
Author(s):  
S. Zwerdling ◽  
K. L. Wang ◽  
Y. C. M. Yeh
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
High Efficiency ◽  
Weight Ratio ◽  
Chemical Vapor ◽  
Oxide Semiconductor ◽  
Large Area ◽  
Coated Metal ◽  
Cvd Growth ◽  
First Time

The present research is directed toward demonstrating the feasibility of producing high-efficiency GaAs solar cells with high power-to-weight ratio by organo-metallic chemical vapor deposition (OM-CVD) growth of thin epi-layers on suitable substrates. Antireflection-coated, metal-oxide-semiconductor (AMOS), GaAs solar cells grown on bulk polycrystalline Ge substrates were initially studied, with the best efficiency achieved being about 9 percent AM1 (7 percent AM0). Subsequently, a new direct deposition method for fabricating ultra-thin top layer, epitaxial n+ /p shallow homojunction solar cells on (100) GaAs substrates (without anodic thinning) was developed by means of which large area (1 cm2) cells were produced with about 19 percent AM1 (15 percent AM0) conversion efficiency. An AM1 conversion efficiency of about 18 percent (14 percent AM0), or about 17 percent (13 percent AM0) with 5 percent grid coverage, was achieved for a single-crystal, GaAs, n+ /p cell grown by OM-CVD on a Ge wafer. These achievements led to the fabrication, for the first time, of thin GaAs epi-layers OM-CVD grown with good crystallographic quality, using a (100) Si-substrate on which a thin Ge epi-interlayer was first deposited by CVD from GeH4 and processed for improved surface morphology.

scholarly journals Fabrication of large-area uniform carbon nanotube foams as near-critical-density targets for laser–plasma experiments

2021 ◽  
Vol 9 ◽  
Author(s):  
Pengjie Wang ◽  
Guijun Qi ◽  
Zhuo Pan ◽  
Defeng Kong ◽  
Yinren Shou ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Critical Density ◽  
Chemical Vapor ◽  
High Energy ◽  
Large Area ◽  
Characterization Methods ◽  
Synthesis Parameters ◽  
High Energy Ions ◽  
Target Characterization ◽  
First Time

Abstract Carbon nanotube foams (CNFs) have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons. Here we report the recent advances in the fabrication technique of such targets. With the further developed floating catalyst chemical vapor deposition (FCCVD) method, large-area ( $>25\kern0.5em {\mathrm{cm}}^2$ ) and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets. The density and thickness of the CNF can be controlled in the range of $1{-}13\kern0.5em \mathrm{mg}/{\mathrm{cm}}^3$ and $10{-}200\kern0.5em \mu \mathrm{m}$ , respectively, by varying the synthesis parameters. The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.

Roll-to-Roll Graphene Synthesis by Using Microwave Plasma Chemical Vapor Deposition at Low Temperature

2012 ◽  
Vol 1401 ◽  
Author(s):  
Takatoshi Yamada ◽  
Masatou Ishihara ◽  
Jaeho Kim ◽  
Masataka Hasegawa ◽  
Sumio Iijima
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Large Area ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Graphene Synthesis ◽  
Film Substrate

ABSTRACTWe reported continuous depositions of grahene films on copper foils with A4 width using roll-to-toll microwave plasma chemical vapor deposition (MWPCVD) technique. A pair of winder and unwinder was built into an MWPCVD apparatus. Surface-wave plasma enabled us to deposit large-area graphene film (substrate stage is of 480 mm x 300 mm) at temperatures below 400 ºC. In Raman spectra, G- and G’-band attributed to graphene were obtained. In addition, Dand D’-band originated from defects and/or edges were detected. These results suggested that the obtained graphene films consisted of flake boundaries and defects. After the transferring graphene onto the polyethylene terephthalate film, uniform transmittance and sheet resistance were confirmed.

Direct Bonding of Silicon Wafers with Simultaneous Dopant Diffusion

2001 ◽  
Vol 681 ◽  
Author(s):  
Igor V. Grekhov ◽  
Tatiana S. Agrunova ◽  
Lioudmila S. Kostina ◽  
Natalia M. Shmidt ◽  
Helmut Föll ◽  
...  
Keyword(s):  
Bonding Interface ◽  
Silicon Surfaces ◽  
Structural Quality ◽  
Water Molecules ◽  
Large Area ◽  
Type Layer ◽  
P Type ◽  
First Time ◽  
Wafer Surfaces

ABSTRACTBonding of silicon surfaces in aqueous solution of compounds containing III and IV impurities was performed for the first time. It was observed that the presence of aluminum at the bonding interface improved structural quality of the interface. This phenomenon is explained by the increase of the contact area due to Al-OH group sandwiched between the water molecules adsorbed at hydrophilic wafer surfaces at the first bonding stage. The incorporation of Al produces a p-type layer and the I/V characteristics of the resultant np+n diodes is shown not to be influenced by the presence of the bonding interface. The technique developed could be advantageous for the design of multi-layer large area semiconductor devices.

High Temperature Operation of A New Normally-Off AlGaN/GaN HFET on Si Substrate

2003 ◽  
Vol 798 ◽  
Author(s):  
Seikoh Yoshida ◽  
Jiang Li ◽  
Takahiro Wada ◽  
Hironari Takehara
Keyword(s):  
Metalorganic Chemical Vapor Deposition ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
The Novel ◽  
Si Substrate ◽  
Gan On Si ◽  
Gan Heterostructure ◽  
P Type ◽  
High Temperature Operation ◽  
First Time

ABSTRACTWe report on the novel normally-off AlGaN/p-type GaN heterojunction field effect transistors (HFETs). We grew the AlGaN/p-GaN heterostructure on p-type Si (111) substrate using a metalorganic chemical vapor deposition (MOCVD). A homogeneous buffer layer was first formed on a Si (111) substrate at 1123 K. After that, AlGaN (30 nm)/high resistive p-type GaN (500 nm) heterostructure was also grown at 1303 K without cracking. We fabricated an HFET using AlGaN/p-type GaN on Si substrate. The ohmic electrode material was Al/Ti/Au and the gate electrode was Pt/Au. The distance between the source and the drain was 0.01 mm. The gate length and width were 2000 nm and 0.15 mm, respectively. As a result, the HFET was operated at the condition of the positive gate bias. The pinch-off voltage was 0 V. A normally-off operation was thus confirmed for the first time. The breakdown voltage of FET was over 250 V. We also confirmed that the normally-off HFET was operated at 573 K for over 150 h.

Multiple Transfer Used on Repairing Transparent and Electric Film Based on CVD - Grown Graphene

2013 ◽  
Vol 774-776 ◽  
pp. 634-639
Author(s):  
Peng Fei Zhao ◽  
Da Wei He ◽  
Yong Sheng Wang ◽  
Ming Fu ◽  
Hong Peng Wu ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Gas Flow ◽  
Graphene Film ◽  
Chemical Vapor ◽  
Monolayer Graphene ◽  
Gas Flow Rate ◽  
Large Area ◽  
Spectroscopy Analysis ◽  
Photoelectric Device ◽  
Grown Graphene

We optimized the CH4 and H2 gas flow rate of chemical vapor deposition (CVD) graphene growth and obtained larger area, fewer-layered graphene grown on Cu foils. After transfering to SiO2 substrate by PMMA more than 3 times to repair the defect of monolayer graphene film, we synthesized large area, transparent and continuous graphene film. The morphology and structure were characterized by SEM and Raman spectroscopy. Analysis of electrical properties and optical properties show that we obtained low resistance and high transparency of ~90%, which could be used on photoelectric device as solar cell and acceptable for replacing commercial ITO electrodes.

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