scholarly journals Correlation of p-doping in CVD Graphene with Substrate Surface Charges

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Goniszewski ◽  
M. Adabi ◽  
O. Shaforost ◽  
S. M. Hanham ◽  
L. Hao ◽  
...  
Keyword(s):  
Contact Angle ◽  
Gate Voltage ◽  
Dirac Point ◽  
Substrate Surface ◽  
Chemical Vapour ◽  
Charge Carrier Density ◽  
Surface Charges ◽  
Large Area ◽  
Cvd Graphene ◽  
Graphene Field Effect Transistor

Abstract Correlations between the level of p-doping exhibited in large area chemical vapour deposition (CVD) graphene field effect transistor structures (gFETs) and residual charges created by a variety of surface treatments to the silicon dioxide (SiO2) substrates prior to CVD graphene transfer are measured. Beginning with graphene on untreated thermal oxidised silicon, a minimum conductivity (σ min ) occurring at gate voltage V g  = 15 V (Dirac Point) is measured. It was found that more aggressive treatments (O2 plasma and UV Ozone treatments) further increase the gate voltage of the Dirac point up to 65 V, corresponding to a significant increase of the level of p-doping displayed in the graphene. An electrowetting model describing the measured relationship between the contact angle (θ) of a water droplet applied to the treated substrate/graphene surface and an effective gate voltage from a surface charge density is proposed to describe biasing of V g at σ min and was found to fit the measurements with multiplication of a correction factor, allowing effective non-destructive approximation of substrate added charge carrier density using contact angle measurements.

scholarly journals Erratum: Corrigendum: Correlation of p-doping in CVD Graphene with Substrate Surface Charges

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
S. Goniszewski ◽  
M. Adabi ◽  
O. Shaforost ◽  
S. M. Hanham ◽  
L. Hao ◽  
...  
Keyword(s):  
Substrate Surface ◽  
Surface Charges ◽  
Cvd Graphene

HIGH FREQUENCY TOP-GATED GRAPHENE RF AMBIPOLAR FETs USING LARGE-AREA CVD GRAPHENE AND ADVANCED DIELECTRICS

2011 ◽  
Vol 1283 ◽  
Author(s):  
Osama M. Nayfeh ◽  
Madan Dubey
Keyword(s):  
Dirac Point ◽  
Gate Dielectric ◽  
Field Effect Transistors ◽  
Hole Mobility ◽  
Monolayer Graphene ◽  
Large Area ◽  
Electron Hole ◽  
Cvd Graphene ◽  
Graphene Fet ◽  
P Type

ABSTRACTAmbipolar top-gated field effect transistors (FETs) based on large area Cu catalyzed CVD-grown monolayer graphene interfaced to advanced dielectrics have been constructed and examined both for their material and electrical qualities. Interfacing of the graphene with novel insulators/substrates could be tailored for the particular application and provide for enhanced device functionality. In contrast to graphene FETs using SiO2-based top-gate dielectric, which show asymmetric electron/hole mobility (with larger hole mobility), and Dirac point shifted to positive levels, FETs constructed using advanced AlN show Dirac point almost near neutral levels and near symmetric electron/hole mobility. The DP is shifted likely due to compensation of the intrinsic p-type doping by n-type doping introduced by the AlN deposition and potentially via a contribution of polarization-induced carrier density. Finally, we demonstrate a top-gated graphene FET with the first observation of RF operation with GHz cut-off frequency based on large area CVD graphene.

scholarly journals Substrate Sensitivity of the Adhesion and Material Properties of RF-PECVD Amorphous Carbon

1999 ◽  
Vol 558 ◽  
Author(s):  
Shashi Paul ◽  
F.J Clough
Keyword(s):  
Amorphous Carbon ◽  
Material Properties ◽  
Electronic Device ◽  
Substrate Surface ◽  
Chemical Vapour ◽  
Growth Conditions ◽  
Spatial Variations ◽  
Large Area ◽  
Interlayer Dielectric ◽  
Self Bias

ABSTRACTHydrogenated amorphous carbon (a-C:H), deposited by the if-plasma enhanced chemical vapour deposition (rf-PECVD) technique, is a promising material for large area electronic and interlayer dielectric applications. The structural and electronic properties of rf-PECVD a-C:H, deposited at room temperature from CH4/He and CH4/Ar gas mixtures, are shown to be sensitive to the substrate on which the thin film is deposited. The choice of substrate (c-Si or C7059 glass), and the existence and geometrical dimensions of any metallic pattern on the substrate surface, can result in significant spatial variations in the a-C:H adhesion and material properties. The observed effects are attributed to potential variations across the metal patterned substrates which influence the ‘local’ dc self-bias. This leads to spatial variations in the growth conditions and hence material properties. For electronic device and dielectric isolation applications this effect can result in significant variations in operating performance. The nature of the substrate and any overlying metallisation pattern are therefore important considerations.

High Resolution Displacement of Functional Groups onto Fluorocarbon Resin Surface by Using ArF Excimer Laser

1996 ◽  
Vol 451 ◽  
Author(s):  
T. Shimizu ◽  
M. Murahara
Keyword(s):  
Contact Angle ◽  
High Resolution ◽  
Laser Beam ◽  
Thin Layer ◽  
Functional Groups ◽  
Excimer Laser ◽  
Laser Fluence ◽  
Large Area ◽  
Three Solutions ◽  
Arf Excimer Laser

ABSTRACTA Fluorocarbon resin surface was selectively modified by irradiation with a ArF laser beam through a thin layer of NaAlO2, B(OH)3, or H2O solution to give a hydrophilic property. As a result, with low fluence, the surface was most effectively modified with the NaAlO2 solution among the three solutions. However, the contact angle in this case changed by 10 degrees as the fluence changed only 1mJ/cm2. When modifying a large area of the surface, high resolution displacement could not be achieved because the laser beam was not uniform in displacing functional groups. Thus, the laser fluence was successfully made uniform by homogenizing the laser beam; the functional groups were replaced on the fluorocarbon resin surface with high resolution, which was successfully modified to be hydrophilic by distributing the laser fluence uniformly.

Patterning Organic Fluorescent Molecules with SAM Patterns

2011 ◽  
Vol 1335 ◽  
Author(s):  
Qiong Wu ◽  
Juanyuan Hao ◽  
Shoulei Shi ◽  
Weifeng Wang ◽  
Nan Lu
Keyword(s):  
Organic Molecules ◽  
Low Cost ◽  
Substrate Surface ◽  
Large Area ◽  
Self Assembled Monolayer ◽  
Storage Duration ◽  
Light Emitting ◽  
High Throughput Method ◽  
Self Assembled ◽  
Fluorescent Molecules

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.

Optimisation of Nickel Aluminising by CVD

2012 ◽  
Vol 323-325 ◽  
pp. 367-372 ◽  
Author(s):  
Patrick J. Masset ◽  
Agnieszka Bogusz ◽  
Jan Sieniawski ◽  
Bartek Wierzba ◽  
Katarzyna Tkacz-Śmiech
Keyword(s):  
Substrate Surface ◽  
Chemical Vapour ◽  
Aluminium Chloride ◽  
Aluminium Content ◽  
Surface Boundary ◽  
Essential Information ◽  
Nial Phase ◽  
Partial Pressures ◽  
State Diffusion ◽  
Surface Boundary Condition

Results Concerning Nickel Aluminisation with Application of Chemical Vapour Deposition Method Are Presented. Two-Step Processing under Investigation Consists of Al Chloride Formation in the Primary Vessel and Al Deposition in the Secondary One. the Initial Gas Stream Is Composed of Hcl Dissolved in H2at Various Ratios. it Was Shown that the Choice of the [HCl]/[H2] Ratio and the Determination of the Optimum Temperature to Produce Most Preferential β-Nial Phase May Be Done with the Use of Thermodynamic Calculations. the Results Obtained with Application of Factsage Program Confirm Essential Influence of both Initial [HCl]/[H2] Ratio (in the Range between 0,05 and 100) and the Temperature in the Second Vessel (1123 K – 1323 K) on Aluminium Chloride Partial Pressures and Hence Aluminium Content in its Gaseous Donors and at the Substrate Surface (boundary Condition for Interdiffusion in Ni-Al System). it Was Confirmed that β-Nial Growth Is Favoured at Low [HCl]/[H2] Ratios and High Temperatures for which Alcl and AlCl2Partial Pressures Increase with Respect to that of AlCl3. the Thermodynamic Predictions Remain in Agreement with CVD Experiments. the Presented Thermodynamic Data May Be Used as a Source of Essential Information for Designing Further Experiments in this Field as Well as for Modelling of Solid-State Diffusion in Ni-Al System.

scholarly journals Photo Initiated Chemical Vapour Deposition To Increase Polymer Hydrophobicity

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ariane Bérard ◽  
Gregory S. Patience ◽  
Gérald Chouinard ◽  
Jason R. Tavares
Keyword(s):  
Contact Angle ◽  
Chemical Vapour Deposition ◽  
High Density Polyethylene ◽  
Vapour Deposition ◽  
Venturia Inaequalis ◽  
Chemical Vapour ◽  
Superhydrophobic Coating ◽  
Water Ingress ◽  
New Challenges ◽  
Lower Contact

Abstract Apple growers face new challenges to produce organic apples and now many cover orchards with high-density polyethylene (HDPE) nets to exclude insects, rather than spraying insecticides. However, rainwater- associated wetness favours the development of apple scabs, Venturia inaequalis, whose lesions accumulate on the leaves and fruit causing unsightly spots. Treating the nets with a superhydrophobic coating should reduce the amount of water that passes through the net. Here we treat HDPE and polyethylene terephthalate using photo-initiated chemical vapour deposition (PICVD). We placed polymer samples in a quartz tube and passed a mixture of H2 and CO through it while a UVC lamp (254 nm) illuminated the surface. After the treatment, the contact angle between water droplets and the surface increased by an average of 20°. The contact angle of samples placed 70 cm from the entrance of the tube was higher than those at 45 cm and 20 cm. The PICVD-treated HDPE achieved a contact angle of 124°. Nets spray coated with a solvent-based commercial product achieved 180° but water ingress was, surprisingly, higher than that for nets with a lower contact angle.

Advances in transferring chemical vapour deposition graphene: a review

2017 ◽  
Vol 4 (6) ◽  
pp. 1054-1063 ◽  
Author(s):  
Mingguang Chen ◽  
Robert C. Haddon ◽  
Ruoxue Yan ◽  
Elena Bekyarova
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Cvd Graphene ◽  
Recent Developments ◽  
Graphene Transfer

This review highlights recent developments in CVD graphene transfer methods from the perspective of mechanism, cleanness, quality, reliability, and cost.

scholarly journals Origin of Mangetotransport Properties in APCVD Deposited Tin Oxide Thin Films

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5182
Author(s):  
Krunoslav Juraić ◽  
Davor Gracin ◽  
Matija Čulo ◽  
Željko Rapljenović ◽  
Jasper Rikkert Plaisier ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Tin Oxide ◽  
Texture Coefficient ◽  
Chemical Vapour ◽  
Visible Spectrum ◽  
Soda Lime ◽  
Fine Tuning ◽  
Soda Lime Glass ◽  
Charge Carrier Density

Transparent conducting oxides (TCO) with high electrical conductivity and at the same time high transparency in the visible spectrum are an important class of materials widely used in many devices requiring a transparent contact such as light-emitting diodes, solar cells and display screens. Since the improvement of electrical conductivity usually leads to degradation of optical transparency, a fine-tuning sample preparation process and a better understanding of the correlation between structural and transport properties is necessary for optimizing the properties of TCO for use in such devices. Here we report a structural and magnetotransport study of tin oxide (SnO2), a well-known and commonly used TCO, prepared by a simple and relatively cheap Atmospheric Pressure Chemical Vapour Deposition (APCVD) method in the form of thin films deposited on soda-lime glass substrates. The thin films were deposited at two different temperatures (which were previously found to be close to optimum for our setup), 590 °C and 610 °C, and with (doped) or without (undoped) the addition of fluorine dopants. Scanning Electron Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GIXRD) revealed the presence of inhomogeneity in the samples, on a bigger scale in form of grains (80–200 nm), and on a smaller scale in form of crystallites (10–25 nm). Charge carrier density and mobility extracted from DC resistivity and Hall effect measurements were in the ranges 1–3 × 1020 cm−3 and 10–20 cm2/Vs, which are typical values for SnO2 films, and show a negligible temperature dependence from room temperature down to −269 °C. Such behaviour is ascribed to grain boundary scattering, with the interior of the grains degenerately doped (i.e., the Fermi level is situated well above the conduction band minimum) and with negligible electrostatic barriers at the grain boundaries (due to high dopant concentration). The observed difference for factor 2 in mobility among the thin-film SnO2 samples most likely arises due to the difference in the preferred orientation of crystallites (texture coefficient).

Neutron Detectors Made From Chemically Vapour Deposited Semiconductors

1997 ◽  
Vol 487 ◽  
Author(s):  
F. Foulon ◽  
P. Bergonzo ◽  
A. Brambilla ◽  
C. Jany ◽  
B. Guizard ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Low Cost ◽  
Chemical Vapour ◽  
Polycrystalline Diamond ◽  
Neutron Detection ◽  
Large Area ◽  
Neutron Detectors ◽  
Gadolinium Isotope ◽  
Neutron Detection Efficiency ◽  
Hydrogenated Amorphous

AbstractIn this paper, we present the results of investigations on the use of semiconductors deposited by chemical vapour deposition (CVD) for the fabrication of neutron detectors. For this purpose, 20 μm thick hydrogenated amorphous silicon (a-Si:H) pin diodes and 100 μm thick polycrystalline diamond resistive detectors were fabricated. The detectors were coupled to a neutron-charged particle converter : a layer of either gadolinium or boron (isotope 10 enriched) deposited by evaporation. We have demonstrated the capability of such neutron detectors to operate at neutron fluxes ranging from 101 to 106 neutrons/cm2.s. The fabrication of large area detectors for neutron counting or cartography through the use of multichannel reading circuits is discussed. The advantages of these detectors include the ability to produce large area detectors at low cost, radiation hardness (∼ 4 Mrad for a-Si:H and ∼ 100 Mrad for diamond), and for diamond, operation at temperatures up to 500°C. These properties enable the use of these devices for neutron detection in harsh environments. Thermal neutron detection efficiency up to 22 % and 3 % are expected by coupling a-Si:H diodes and diamond detectors to 3 μm thick gadolinium (isotope 157) and 2 μm thick boron layers, respectively.

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