Defect density in a metal-monolayer-metal cell

1980 ◽  
Vol 33 (8) ◽  
pp. 1713 ◽  
Author(s):  
IR Peterson
Keyword(s):  
Defect Density ◽  
High Surface ◽  
Langmuir Blodgett ◽  
Minimum Deformation ◽  
Defect Densities

Techniques for Langmuir-Blodgett monolayer deposition at high surface pressures and with minimum deformation have been studied by measurement of the resultant defect densities in a metal-monolayer-metal cell.

Metastability in Monolayer Films Transferred onto Solid Substrates by the Langmuir-Blodgett Method: IR Evidence for Transfer-Induced Phase Transitions

1994 ◽  
Vol 48 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
Fazale R. Rana ◽  
Suci Widayati ◽  
Brian W. Gregory ◽  
Richard A. Dluhy
Keyword(s):  
Fatty Acid ◽  
Conformational Changes ◽  
Structural Changes ◽  
High Surface ◽  
Solid Substrate ◽  
Water Interface ◽  
Monolayer Films ◽  
Langmuir Blodgett ◽  
Monomolecular Film ◽  
Air Water Interface

The rate at which a monomolecular film is deposited onto a solid substrate in the Langmuir-Blodgett process of preparing supported monolayer films influences the final structure of the transferred film. Attenuated total reflectance infrared spectroscopic studies of monolayers transferred to germanium substrates show that the speed at which the substrate is drawn through the air/water interface influences the final conformation in the hydrocarbon chains of amphiphilic film molecules. This transfer-induced effect is especially evident when the monolayer is transferred from the expanded region of surface-pressure-molecular-area isotherms at low surface pressures; the effect is minimized when the film molecules are transferred from condensed phases at high surface pressures. This phenomenon has been observed for both a fatty acid and a phospholipid, which suggests that these conformational changes may occur in a variety of hydrocarbon amphiphiles transferred from the air/water interface. This conformational ordering may be due to a kinetically limited phase transition taking place in the meniscus formed between the solid substrate and aqueous subphase. In addition, the results obtained for both the phospholipid and fatty acid suggest that the structure of the amphiphile may help determine the extent and nature of the transfer-speed-induced structural changes taking place in the monomolecular film.

Growth and Characterization of 2″ 6H-Silicon Carbide

1999 ◽  
Vol 572 ◽  
Author(s):  
Erwin Schmitt ◽  
Robert Eckstein ◽  
Martin Kölbl ◽  
Amd-Dietrich Weber
Keyword(s):  
Silicon Carbide ◽  
Boundary Conditions ◽  
Growth Process ◽  
Defect Density ◽  
Crystal Quality ◽  
Process Conditions ◽  
Thermal Boundary Conditions ◽  
Sublimation Growth ◽  
Defect Densities

ABSTRACTFor the growth of 2″ 6H-SiC a sublimation growth process was developed. By different means of characterization crystal quality was evaluated. Higher defect densities, mainly in the periphery of the crystals were found to be correlated to unfavourable process conditions. Improvement of thermal boundary conditions lead to a decreased defect density and better homogeneity over the wafer area.

Investigation of the Defect Size and Density in Thin SiON Filmfor Organic Device Encapsulation

2016 ◽  
Vol 2016 (1) ◽  
pp. 000272-000276
Author(s):  
Kunmo Chu ◽  
Ki Deok Bae ◽  
Byong Gwon Song ◽  
Yong Young Park ◽  
Jaekwan Kim ◽  
...  
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Defect Size ◽  
Intrinsic Defect ◽  
Ni Substrate ◽  
Defect Site ◽  
Defect Sites ◽  
Chemical Vapor Deposited ◽  
Density Values ◽  
Defect Densities

Abstract In this study, thin SiON was grown by plasma enhanced chemical vapor deposited (PECVD) method as a thin-film encapsulation (TFE) layer. For defect visualization, electroplating results in a Cu bump grown at each defect site in the SiON film where electrolytic solution establishes contact with the Ni substrate. It was inferred that the Cu bump density could be representative of the intrinsic defect densities for the SiON film. The defect density values were obtained by monitoring the Cu bumps grown at defect sites in the SiON films and then evaluating the number of densities of the Cu bumps for the corresponding defect densities.At the same time, by analyzing the cross section of the Cu bumps grown on SiON film, a linear relation between the Cu bump diameter and the defect size increase was obtained. We expect that this electroplating method allows for rapid visualization of defect distribution and quality evaluation of TFE layers.

Saturation behavior of the Light-Induced Defect Density in Hydrogenated Amorphous Silicon

1990 ◽  
Vol 192 ◽  
Author(s):  
H. R. Park ◽  
J. Z. Liu ◽  
P. Roca i Cabarrocas ◽  
A. Maruyama ◽  
M. Isomura ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Urbach Energy ◽  
Defect Density ◽  
Generation Rate ◽  
Carrier Generation ◽  
Defect Generation ◽  
Ion Laser ◽  
Hydrogenated Amorphous ◽  
Defect Densities

ABSTRACTUsing a Kr ion laser (λ = 647.1 nm) to produce a carrier generation rate G of 3 × 1020 cm−3s−1, we have saturated the light-induced defect generation in hydrogenated (and fluorinated) amorphous silicon (a-Si:H(F)), within a few hours near room temperature. While the defect generation rate scales roughly with 1/G2, the saturation defect densities Ns,sat are essentially independent of G. The saturation is not due to thermal annealing. We have further measured Ns,sat m 37 a-Si:H(F) films grown in six different reactors under different conditions. The results show that Ns,sat lies between 5 × 1016 and 2 × 1017 cm−3, that Ns,sat drops with decreasing optical gap and hydrogen content, and that Ns,sat is not correlated with the initial defect density or with the Urbach energy.

Correlation Between Freeze-In Temperature of Defect Density and Hydrogen Concentration in a-Si:H

1991 ◽  
Vol 219 ◽  
Author(s):  
X. Xu ◽  
M. Isomura ◽  
J. H. Yoon ◽  
S. Wagner ◽  
J. R. Abelson
Keyword(s):  
Hydrogen Concentration ◽  
Defect Density ◽  
Dangling Bond ◽  
Bond Density ◽  
Higher Temperature ◽  
Defect Densities

ABSTRACTWe measured the freeze-in temperature of the dangling-bond density in a-Si:H in nine samples with hydrogen concentrations ranging from 7.0 to 31 at.%. The measurements were made by determining the defect density of samples quenched from successively higher temperature. We determined the defect densities with the constant photoconductivity method. The freeze-in temperature is 211±10 °C, and is independent of hydrogen concentration.

Capacitance and Transient Photocapacitance Studies of Tetrahedral Amorphous Carbon

2000 ◽  
Vol 621 ◽  
Author(s):  
Kimon C. Palinginis ◽  
A. Ilie ◽  
W.I. Milne ◽  
J. David Cohen
Keyword(s):  
Amorphous Carbon ◽  
Urbach Energy ◽  
Defect Density ◽  
Intrinsic Property ◽  
Band Tail ◽  
Junction Capacitance ◽  
Tetrahedral Amorphous Carbon ◽  
Thermally Activated ◽  
A Value ◽  
Defect Densities

ABSTRACTWe have applied junction capacitance and transient photocapacitance measurements to undoped tetrahedral amorphous carbon (ta-C)/silicon carbide (SiC) heterostructures to deduce defect densities and defect distributions in ta-C. The junction capacitance measurements show two thermally activated processes. One can be related to the activation of carriers out of defects at the ta-C/SiC interface while the other one with an activation energy of 0.36eV is an intrinsic property of the ta-C. The defect density at the ta-C/SiC interface is estimated to be roughly 9 ± 2 × 109 cm−2. The transient photocapacitance measurements have allowed us to observe the broader band tail of ta-C, giving a value (Urbach energy) of 230meV.

CHARACTERIZATION OF CdZnTe CRYSTALS BY RESISTIVITY MEASUREMENTS AND CHEMICAL ETCHING

2002 ◽  
Vol 16 (17) ◽  
pp. 615-619
Author(s):  
Q. R. HOU ◽  
Y. B. CHEN ◽  
H. CHEN ◽  
Y. J. HE ◽  
K. Y. LIU
Keyword(s):  
Chemical Etching ◽  
Defect Density ◽  
Radiation Detectors ◽  
High Quality ◽  
Density Region ◽  
Resistivity Measurements ◽  
High Defect Density ◽  
Vertical Bridgman ◽  
Defect Densities

CdZnTe crystals grown by the vertical Bridgman method were characterized by measuring their resistivity and chemical etching in the well-known Nakagawa etchant (3HF:2H2O2:2H2O, vol./vol.). It was found that the resistivity of the CdZnTe crystals was between 4.33 × 103 and 8.50 × 106 Ωcm. Defect densities were much higher around the periphery of some CdZnTe samples due to the influence of mechanical stress caused by contact with the crucible walls during the CdZnTe crystal growth. The sizes of the high defect density region ranged from 1.8 to 2.8 mm. Such high defect density region should be eliminated in order to make high-quality radiation detectors or prepare the substrates for the epitaxial growth of HgCdTe.

scholarly journals Growth Condition-Oriented Defect Engineering for Changes in Au–ZnO Contact Behavior from Schottky to Ohmic and Vice Versa

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 980 ◽  
Author(s):  
Abu Rana ◽  
Hyun-Seok Kim
Keyword(s):  
Schottky Barrier ◽  
Carrier Concentration ◽  
Carrier Transport ◽  
Defect Density ◽  
High Surface ◽  
Zno Nanorods ◽  
Schottky Contact ◽  
Oxygen Plasma Treatment ◽  
Defect Engineering ◽  
Contact Behavior

ZnO has the built-in characteristics of both ionic and covalent compound semiconductors, which makes the metal–ZnO carrier transport mechanism quite intricate. The growth mechanism-centric change in ZnO defect density and carrier concentration also makes the contact formation and behavior unpredictable. This study investigates the uncertainty in Au–ZnO contact behavior for application-oriented research and the development on ZnO nanostructures. Herein, we explain the phenomenon for how Au–ZnO contact could be rectifying or non-rectifying. Growth method-dependent defect engineering was exploited to explain the change in Schottky barrier heights at the Au–ZnO interface, and the change in device characteristics from Schottky to Ohmic and vice versa. The ZnO nanorods were fabricated via aqueous chemical growth (ACG) and microwave-assisted growth (MAG) methods. For further investigations, one ACG sample was doped with Ga, and another was subjected to oxygen plasma treatment (OPT). The ACG and Ga-doped ACG samples showed a quasi-Ohmic and Ohmic behavior, respectively, because of a high surface and subsurface level donor defect-centric Schottky barrier pinning at the Au–ZnO interface. However, the ACG-OPT and MAG samples showed a more pronounced Schottky contact because of the presence of low defect-centric carrier concentration via MAG, and the removal of the surface accumulation layer via the OPT process.

Reduction of Defects in GaN Epitaxial Films Grown Heteroepitaxially on SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1483-1488 ◽  
Author(s):  
Charles R. Eddy ◽  
N.D. Bassim ◽  
Michael A. Mastro ◽  
R.L. Henry ◽  
Mark E. Twigg ◽  
...  
Keyword(s):  
Defect Density ◽  
Device Performance ◽  
Nucleation Layer ◽  
Lattice Match ◽  
Extended Defect ◽  
Dislocation Densities ◽  
Previous State ◽  
Step Density ◽  
Defect Densities ◽  
Very High

Silicon carbide (SiC) has become the substrate of choice for III-N epilayers applied to electronic devices due to the lack of a native III-N substrate. This is particularly true for high power applications, since the thermal conductivity of the substrate enhances device performance. Although the GaN lattice match is slightly better for SiC than for sapphire, the dislocation densities that result are still very high (generally in the high 108 cm-2 range) and often deleterious to device performance. Screw-component dislocations are especially critical since they serve as leakage paths in vertically conducting III-N devices. In this paper efforts to reduce the extended defect density in III-N films grown on SiC will be reviewed. Details on recent efforts to use step-free SiC mesa surfaces arrayed on commercial 4HSiC substrates will then be highlighted showing dramatic reductions in extended defect densities and the virtual elimination of critical defects for vertically conducting devices. In these experiments, SiC surfaces that are homoepitaxially grown step-free or of very low step density have been used as growth templates for thin (<3 μm) GaN films deposited on a novel 1000 Å AlN nucleation layer characterized by a total dislocation density two orders of magnitude lower than the previous state-of-the-art, and with no evidence of screw-component dislocations.

Defect Reduction of Cvd-Grown Cubic SiC Epitaxial Films on Off-Axis Si(100) Substrates with a Novel Off-Direction.

1990 ◽  
Vol 198 ◽  
Author(s):  
Katsuki Furukawa ◽  
Yoshihisa Fujii ◽  
Akira Suzuki ◽  
Shigeo Nakajima
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Defect Reduction ◽  
Fault Density ◽  
Electrolytic Etching ◽  
Order Of Magnitude ◽  
First Time ◽  
Defect Densities ◽  
Sic Films

ABSTRACTMonocrystalline cubic SiC (β -SiC) thin films with lower defect densities have been epitaxially grown by chemical vapor deposition on off-axis Si (100) substrates with off-directions different from the conventional 〈011〉. Stacking faults of β -SiC films are investigated by the electrolytic etching and SEM observation. The effects of off-direction deviated from 〈011〉 are examined for the first time. The off-angle is fixed at 2 degrees. We find a reduction in defect density with increasing deviation angle θ, of off-direction from [011] toward [011[ (θ = 0 - 45°). The defect density becomes one order of magnitude smaller than that of on-axis (100) substrates. A typical value of the stacking fault density is approximately 6 × 106 cm−2 on the substrate with θ = 30° (film thickness: 24μ m).

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