Laser direct writing of graphene patterns

2011 ◽  
Vol 1365 ◽  
Author(s):  
J.B. Park ◽  
W. Xiong ◽  
Z.Q. Xie ◽  
M. Mitchell ◽  
Y. Gao ◽  
...  
Keyword(s):  
Single Layer ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Single Layer Graphene ◽  
Direct Writing ◽  
Optically Pumped ◽  
Scan Speed ◽  
Thin Nickel ◽  
532 Nm

ABSTRACTRapid growth of single-layer graphene using laser-induced chemical vapor deposition (LCVD) with a visible CW laser (λ = 532 nm) irradiation at room temperature was investigated. In this study, an optically-pumped solid-state laser with a wavelength of 532 nm irradiates a thin nickel foil to induce a local temperature rise, thereby allowing the direct writing of graphene patterns about ~10 μm in width with high growth rate on precisely controlled positions. It is demonstrated that the fabrication of graphene patterns can be achieved with a single scan for each graphene pattern using LCVD with no annealing or preprocessing of the substrate. The scan speed reaches to about ~50 um/s, which indicates that the graphene pattern with 1:1 aspect ratio (x:y) can be grown in 0.2 sec. The patterned graphene on nickel was transferred to SiO2/Si substrate for fabrication of electrical circuits and sensor devices.

Mocvd SrS:Ce for Applications in Electroluminescent Devices

1997 ◽  
Vol 471 ◽  
Author(s):  
D. Endisch ◽  
K. Barth ◽  
J. Lau ◽  
G. Peterson ◽  
A. E. Kaloyeros ◽  
...  
Keyword(s):  
Process Development ◽  
Process Integration ◽  
Low Cost ◽  
Chemical Vapor ◽  
High Growth ◽  
Film Structure ◽  
High Growth Rate ◽  
Organic Chemical ◽  
Glass Substrates ◽  
Full Color

ABSTRACTSrS:Ce is an important material for full color electroluminescent (EL) flat panel displays. Using a combination of SrS:Ce/ZnS:Mn and appropriate color filters high quality full color displays have been demonstrated [1]. Major issues for commercially viable process integration of SrS:Ce are the combination of high luminance, high growth rate, and process temperatures below 600°C for compatibility with low cost glass substrates. This work describes the process development and optimization of metal-organic chemical vapor deposition (MOCVD) of SrS:Ce. MOCVD is a promising candidate for deposition of SrS:Ce because it can provide the required growth rates and allows control of crystal structure and stoichiometry. Growth of SrS:Ce was performed in the temperature range from 400°C to 530°C using Sr(tmhd)2, Ce(tmhd)4, and H2S as precursors. The structure of the SrS:Ce was found to be strongly dependent on the H2S flow. A brightness of 15 fL and an efficiency of 0.22 lm/W has been achieved (40 V above threshold voltage, 60 Hz AC). Film analysis included Rutherford backscattering (RBS), X-ray diffraction (XRD), atomic force microscopy (AFM), and EL measurements. Results on the correlation between process parameters, film structure, grain size and EL performance will be presented.

Epitaxial Chemical Vapor Deposition Growth of Single-Layer Graphene over Cobalt Film Crystallized on Sapphire

ACS Nano ◽  
2010 ◽  
Vol 4 (12) ◽  
pp. 7407-7414 ◽  
Author(s):  
Hiroki Ago ◽  
Yoshito Ito ◽  
Noriaki Mizuta ◽  
Kazuma Yoshida ◽  
Baoshan Hu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Chemical Vapor Deposition Growth ◽  
Cobalt Film ◽  
Layer Graphene

Performance of single layer graphene obtain by chemical vapor deposition on gold electrodes

2019 ◽  
Vol 98 ◽  
pp. 107510 ◽  
Author(s):  
Bianca Tincu ◽  
Ioana Demetrescu ◽  
Andrei Avram ◽  
Vasilica Tucureanu ◽  
Alina Matei ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Gold Electrodes ◽  
Layer Graphene

Chemical Vapor Deposited Graphene for Opto-Electronic Applications

2016 ◽  
Vol 39 ◽  
pp. 57-68
Author(s):  
Vikram Passi ◽  
Amit Gahoi ◽  
Sarah Riazimehr ◽  
Stefan Wagner ◽  
Andreas Bablich ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Spectral Response ◽  
Single Layer ◽  
Chemical Vapor ◽  
Adsorbed Water ◽  
Single Layer Graphene ◽  
Ambient Conditions ◽  
Transfer Length ◽  
Type Silicon ◽  
P Type

In this work, fabrication and characterisation of graphene photodiodes and transfer length method structures is presented. Graphene growth is carried out using a thermal chemical vapor deposition process on copper foils and subsequently transferred onto silicon-dioxide/silicon substrate. Comparison of electrical and optical characteristics of the photodiodes, which are fabricated on both n-type and p-type silicon, is shown. The photodiodes fabricated on n-type silicon show good rectifying behaviour when compared with photodiodes fabricated on p-type silicon. Spectral response of graphene photodiodes is measured to be less than 0.2 mAW-1 which is attributed to the light absorbance of 2.3% for single layer graphene. Transfer length method device structures are also fabricated and contact resistance is calculated and plotted as a function of spacing between the contacts. The calculated contact resistance (RcW) is 0.87 kΩ.µm. The latter structures are also characterised under various ambient conditions, before and after annealing. The value of contact resistance reduces from 0.87 kΩ.µm to 0.75 kΩ.µm after annealing. This reduction is attributed to the improvement in bonding between graphene and metal. Measurements under vacuum show an increase in contact resistance which is attributed to the removal of adsorbed water molecules on the surface on graphene. The sheet resistivity of graphene is calculated to be between 1.17 kΩ/□ and 3.67 kΩ/□.

Guiding Principle to Develop Intrinsic Microcrystalline Silicon Absorber Layer For Solar Cell By Hot-Wire Cvd

2001 ◽  
Vol 664 ◽  
Author(s):  
A. R. Middya ◽  
U. Weber ◽  
C. Mukherjee ◽  
B. Schroeder
Keyword(s):  
Growth Rate ◽  
Solar Cell ◽  
Cell Structure ◽  
Short Circuit ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Open Circuit ◽  
Hot Wire ◽  
Microcrystalline Silicon

ABSTRACTWe report on ways to develop device quality microcrystalline silicon (μc-Si:H) intrinsic layer with high growth rate by hot-wire chemical vapor deposition (HWCVD). With combine approach of controlling impurities and moderate H-dilution [H2/SiH4 ͌ 2.5], we developed, for the first time, highly photosensitive (103 μc-Si:Hfilms with high growth rate (>1 nm/s); the microstructure of the film is found to be close to amorphous phase (fc ͌ 46 ̻± 5%). The photosensitivity systematically decreases with fc and saturates to 10 for fc> 70%. On application of these materials in non-optimized pin [.proportional]c-Si:H solar cell structure yields 700 mV open-circuit voltage however, surprisingly low fill factor and short circuit current. The importance of reduction of oxygen impurities [O], adequate passivation of grain boundary (GB) as well as presence of inactive GB of (220) orientation to achieve efficient [.proportional]c-Si:H solar cells are discussed.

Halide-CVD Growth of Bulk SiC Crystals

2006 ◽  
Vol 527-529 ◽  
pp. 21-26 ◽  
Author(s):  
A.Y. Polyakov ◽  
Mark A. Fanton ◽  
Marek Skowronski ◽  
Hun Jae Chung ◽  
Saurav Nigam ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Growth ◽  
High Growth Rate ◽  
Flow Ratio ◽  
Novel Approach ◽  
Cvd Growth ◽  
Electron And Hole Traps ◽  
Separate Injection

A novel approach to the high growth rate Chemical Vapor Deposition of SiC is described. The Halide Chemical Vapor Deposition (HCVD) method uses SiCl4, C3H8 (or CH4), and hydrogen as reactants. The use of halogenated Si source and of separate injection of Si and C precursors allows for preheating of source gases without causing premature chemical reactions. The stoichiometry of HCVD crystals can be controlled by changing the C/Si flow ratio and can be kept constant throughout growth, in contrast to the Physical Vapor Transport technique. HCVD was demonstrated to deposit high crystalline quality, very high purity 4H- and 6H-SiC crystals with growth rates comparable to other bulk SiC growth techniques. The densities of deep electron and hole traps are determined by growth temperature and C/Si ratio and can be as low as that found in standard silane-based CVD epitaxy. At high C/Si flow ratio, the resistivity of HCVD crystals exceeds 105 _cm. These characteristics make HCVD an attractive method to grow SiC for applications in high-frequency and/or high voltage devices.

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