Surface Condition in the Plasma-CVD of a-Si:H,F from SiF4 and H2

1988 ◽  
Vol 131 ◽  
Author(s):  
A. Maruyama ◽  
D. S. Shen ◽  
V. Chu ◽  
J. Z. Liu ◽  
J. Jaroker ◽  
...  
Keyword(s):  
Surface State ◽  
Growth Temperature ◽  
Urbach Energy ◽  
Film Growth ◽  
Surface Condition ◽  
Surface States ◽  
State Density ◽  
Growth Surface ◽  
Plasma Cvd ◽  
Band Tail

ABSTRACTWe present a detailed study of the growth of a-Si:H,F from SiF4 and H4. The growth surface appears to have a high density of surface states. These surface states can be thermally relaxed by keeping the films at growth temperature after the termination of growth, suggesting that the states were created during film growth. When frozen in, the surface state density is found to depend on the conditions during film growth. The density is related to the sharpness of the valence band tail as measured by the Urbach Energy. We believe that a reaction on the growth surface resulting in fluorine elimination creates these surface states and also affects the formation of the Si-network.

Researches concerning the Aerodynamic Sorting of Solid Particles According to the Surface States

2008 ◽  
Vol 59 (3) ◽  
pp. 360-365 ◽  
Author(s):  
Valentin Nedeff ◽  
Emilian Mosnegutu ◽  
Mirela Panainte ◽  
Carment Savin ◽  
Bogdan Macarescu
Keyword(s):  
Binary Mixture ◽  
Rough Surface ◽  
Surface State ◽  
Smooth Surface ◽  
Surface Condition ◽  
Surface States ◽  
Aerodynamic Characteristics ◽  
Solid Particles ◽  
Separation Degree ◽  
Sorting Process

The process of aerodynamic sorting of a solid particles mixture is influenced by the aerodynamic characteristics of the particles (shape, dimensions, the surface state and the density of the particle), which determine the behaviour of particles in the air flows. In this study it was analyzed the influence of the surface state of solid particles on the separation degree of a binary mixture, made from particles with smooth surface and particles with rough surface, submitted to the aerodynamic sorting. The correlation between the surface state of solid particles and their behavior in air flow is emphasized by the weight mass of the particles deposited in the collection boxes. It was observed that the particles with the smooth surface have higher floating velocities than the particles with the rough surface for closed dimensions, shapes and densities. The sorting process is influenced by the surface condition of the particle.

Novel Oxides for Passivating AlGaN/GaN HEMT and Providing Low Surface State Densities at Oxide/GaN Interface

2003 ◽  
Vol 764 ◽  
Author(s):  
F. Ren ◽  
B. Luo ◽  
J. Kim ◽  
R. Mehandru ◽  
B. P. Gila ◽  
...  
Keyword(s):  
Surface State ◽  
Communication Systems ◽  
Surface Passivation ◽  
Surface States ◽  
Interface State ◽  
High Energy ◽  
State Density ◽  
Oxide Semiconductor ◽  
High Electron ◽  
State Densities

Both MgO and Sc2O3 are shown to provide low interface state densities (in the 1011 eV-1 cm-2 range) on n- and p-GaN, making them useful for surface passivation layers to mitigate current collapse in GaN/AlGaN high electron mobility transistors(HEMTs) and also gate dielectrics for metal-oxide semiconductor(MOS) devices. Clear evidence of inversion has been demonstrated in gate-controlled MOS p-GaN diodes using both types of oxide. Charge pumping measurements on diodes undergoing a high temperature implant activation anneal show a total surface state density of ∼3 × 1012 cm-2. On HEMT structures, both oxides provide effective passivation of surface states and these devices show improved output power. The MgO/GaN diodes and Sc2O3 passivated HEMT are also found to be quite radiation-resistant, making them attractive for satellite and terrestrial communication systems requiring a high tolerance to high energy(40MeV) protons.

Determination of surface barrier height and surface state density in GaN films grown on sapphire substrates

2004 ◽  
Vol 831 ◽  
Author(s):  
Seong-Eun Park ◽  
Joseph J. Kopanski ◽  
Youn-Seon Kang ◽  
Lawrence H. Robins ◽  
Hyun-Keel Shin
Keyword(s):  
Barrier Height ◽  
Surface State ◽  
Deep Level ◽  
Surface States ◽  
State Density ◽  
Beam Power ◽  
Surface Barrier ◽  
Surface State Density ◽  
Sapphire Substrates ◽  
Surface Electric Field

ABSTRACTPhotoreflectance (PR) modulation spectroscopy was performed to investigate surface properties of GaN films grown on sapphire substrates. From the period of the Franz-Keldysh oscillations, the surface electric field across the GaN space charge region was found to be (197 ± 11) kV/cm, which corresponds to a surface state density of 1.0×1012 cm−2. A surface barrier height of 0.71 eV was determined by fitting the dependence of the PR intensities on pump beam power density. We suggest that a deep level is formed at 2.68 eV above the GaN valence band edge due to the large density of surface states.

scholarly journals Road Surface State Recognition Based on SVM Optimization and Image Segmentation Processing

2017 ◽  
Vol 2017 ◽  
pp. 1-21 ◽  
Author(s):  
Jiandong Zhao ◽  
Hongqiang Wu ◽  
Liangliang Chen
Keyword(s):  
Image Segmentation ◽  
Surface State ◽  
Traffic Accidents ◽  
Surface Condition ◽  
Surface States ◽  
Road Surface ◽  
Support Vector ◽  
Image Size ◽  
State Recognition ◽  
Penalty Factor

Adverse road condition is the main cause of traffic accidents. Road surface condition recognition based on video image has become a central issue. However, hybrid road surface and road surface under different lighting environments are two crucial problems. In this paper, the road surface states are categorized into 5 types including dry, wet, snow, ice, and water. Then, according to the original image size, images are segmented; 9-dimensional color eigenvectors and 4 texture eigenvectors are extracted to construct road surface state characteristics database. Next, a recognition method of road surface state based on SVM (Support Vector Machine) is proposed. In order to improve the recognition accuracy and the universality, a grid searching algorithm and PSO (Particle Swarm Optimization) algorithm are used to optimize the kernel function factor and penalty factor of SVM. Finally, a large number of actual road surface images in different environments are tested. The results show that the method based on SVM and image segmentation is feasible. The accuracy of PSO algorithm is more than 90%, which effectively solves the problem of road surface state recognition under the condition of hybrid or different video scenes.

Control of the Electron and Hole Drift mobilities in Plasma Deposited a-Si:H

1994 ◽  
Vol 336 ◽  
Author(s):  
Gautam Ganguly ◽  
Akihisa Matsuda
Keyword(s):  
Room Temperature ◽  
Film Growth ◽  
Drift Mobility ◽  
Growth Surface ◽  
Band Tail ◽  
Capacitively Coupled ◽  
Deposition Parameters ◽  
Optimum Energy ◽  
Temperature Dependences ◽  
Stimulation Of

ABSTRACTThe ‘time-of-flight’ technique measured electron and hole drift mobilities are shown to be independent of deposition parameters in capacitively coupled, diode type RF-PECVD a-Si:H. However, the carrier mobilities can be varied by orders of magnitude by changing the bias applied to the mesh type controlling electrode in a triode type reactor. The room temperature hole drift mobility increases to 10−1cm2/Vs when an appropriate bias is applied to the mesh providing optimum energy ion stimulation of the film growth surface during deposition. Analysis of the field and temperature dependences of the drift mobilities shows that in the best specimens the conduction (valence) band tail density of states are approximately exponential with a reciprocal slope of lOMeV (25MeV).

In-Situ Characterization of the Surface State Density by Photoluminescence During Electrochemical Treatments of Silicon Surfaces

1996 ◽  
Vol 451 ◽  
Author(s):  
T. Dittrich ◽  
V. Y. Timoshenko ◽  
J. Rappich
Keyword(s):  
Anodic Oxidation ◽  
Surface State ◽  
Surface States ◽  
State Density ◽  
Silicon Surfaces ◽  
In Situ Characterization ◽  
Surface State Density ◽  
Pl Intensity

ABSTRACTThe photoluminescence (PL) of c-Si is probed stroboscopically with single pulses of a N2 laser during electrochemical treatments (hydrogenation and anodic oxidation). The PL intensity of indirect semiconductors such as Si is controlled by the non-radiative surface and bulk recombination. By this reason the density of surface states can be estimated for unknown surfaces by using a calibrated standard. The surface state density of a hydrogenated Si surface increases by exchanging the electrolyte by gaseous N2 or water.

scholarly journals Effect of Point Defects on Electronic Properties and Structure of Talc (001) Surface by First Principles

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Xindi Ma ◽  
Huicong Du ◽  
Ping Lan ◽  
Jianhua Chen ◽  
Lihong Lan
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Surface States ◽  
State Density ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Impurity Atoms ◽  
Electron State Density ◽  
Calculation Results ◽  
Impurity Defects

The surface structure and electronic properties of Mg vacancy defects on talc (001) and impurity defects with Fe, Mn, Ni, Al, and Ca replacing Mg atoms were calculated by using density functional theory. The calculation results show that the order of impurity substitution energy is Mn < Ni < Al < Ca < Fe. This indicates that Fe impurity defects are most easily formed in talc crystals. The covalent bonding between Si atoms and reactive oxygen atoms adjacent to impurity atoms is weakened and the ionic property is enhanced. The addition of Fe, Mn, and Ni atoms makes the surface of talc change from an insulator to a semiconductor and enhances its electrical conductivity. The analysis of electron state density shows that surface states composed of impurity atoms 4S orbital appear near the Fermi level.

Characterization of Wet Chemical Atomic Layer Etching of InGaAs

2021 ◽  
Vol 314 ◽  
pp. 95-98
Author(s):  
Tomoki Hirano ◽  
Kenya Nishio ◽  
Takashi Fukatani ◽  
Suguru Saito ◽  
Yoshiya Hagimoto ◽  
...  
Keyword(s):  
Surface Condition ◽  
Atomic Layer ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Etching Process ◽  
Wet Chemical ◽  
Oxide Removal ◽  
Atomic Layer Etching

In this work, we characterized the wet chemical atomic layer etching of an InGaAs surface by using various surface analysis methods. For this etching process, H2O2 was used to create a self-limiting oxide layer. Oxide removal was studied for both HCl and NH4OH solutions. Less In oxide tended to remain after the HCl treatment than after the NH4OH treatment, so the combination of H2O2 and HCl is suitable for wet chemical atomic layer etching. In addition, we found that repetition of this etching process does not impact on the oxide amount, surface roughness, and interface state density. Thus, nanoscale etching of InGaAs with no impact on the surface condition is possible with this method.

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