Effect of GaAs (100) substrate misorientation on the electrical parameters and surface morphology of metamorphic In0.7Al0.3As/In0.75Ga0.25As/In0.7Al0.3As HEMT nanoheterostructures

2014 ◽  
Vol 48 (1) ◽  
pp. 63-68 ◽  
Author(s):  
G. B. Galiev ◽  
S. S. Pushkarev ◽  
I. S. Vasil’evskii ◽  
E. A. Klimov ◽  
A. N. Klochkov ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Electrical Parameters

scholarly journals Исследование вольт-амперных характеристик новых гетероструктур MnO-=SUB=-2-=/SUB=-/GaAs(100) и V-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=-/GaAs(100), прошедших термическую обработку

2019 ◽  
Vol 53 (8) ◽  
pp. 1074
Author(s):  
Б.В. Сладкопевцев ◽  
Г.И. Котов ◽  
И.Н. Арсентьев ◽  
И.С. Шашкин ◽  
И.Я. Миттова ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Thermal Oxidation ◽  
Current Density ◽  
Chemical Bonding ◽  
Room Temperature ◽  
Reverse Bias ◽  
Electrical Parameters ◽  
Internal Interface ◽  
Current Voltage ◽  
Bias Range

AbstractComplex oxide films with a thickness of about 200 nm are formed during the thermal oxidation of GaAs with magnetron-deposited V_2O_5 and MnO_2 nanolayers. The electrical parameters of the films (reverse-bias breakdown voltage and current density) are determined by the method of current–voltage ( I – V ) characteristics at room temperature in the bias range from –5 to +5 V, and their composition and surface morphology are investigated. It is shown that V_2O_5 facilitates the more intense (in comparison with MnO_2) chemical bonding of arsenic at the internal interface with the formation of As_2O_5. As a result, thermally oxidized V_2O_5/GaAs heterostructures exhibit higher breakdown voltages.

scholarly journals Volume Resistivity of Viton Polymer under Thermal Aging

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 773
Author(s):  
Alireza Abdihamzehkolaei ◽  
Md Tanvir Ahad ◽  
Zahed Siddique
Keyword(s):  
Surface Morphology ◽  
Resistivity Measurement ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Poor Performance ◽  
Volume Resistivity ◽  
Detailed Comparison ◽  
Aged Sample ◽  
Electrical Parameters ◽  
Transient Effect

This study examines the influence of various electrical parameters on the volume resistivity of the Viton fluoroelastomer. The transient current, the temperature dependence of volume resistivity, the voltage dependence of resistivity, and the surface morphology of Viton insulators are investigated for new and aged specimens. An accelerated aging process has been employed in order to simulate the natural aging of insulators in service. A detailed comparison between the new and aged samples is presented. The transient effect, which is a challenge to the resistivity measurement of insulators, has been investigated. The first 60 s of the resistivity measurement test showed a significant influence from the transient effect and should be excluded from the data. The volume resistivity of both new and aged samples decreased when the temperature increased. However, the resistivity of the aged sample was lower than the new one at all tested temperatures. When the temperature increased from 35 to 190 °C, resistivity decreased from 4.77 × 1010 to 6.99 × 108 Ω-cm for the new sample and from 2.6 × 1010 to 6.68 × 108 Ω-cm for the aged sample under 500 V. Additionally, the results from this study showed that the volume resistivity is inversely proportional to the applied voltage. Finally, scanning electron microscope (SEM) micrographs/images allowed us to closely examine the surface morphology of new and aged Viton samples. The surface of aged samples has been recognized with higher surface roughness and more significant surface cracks leading to poor performance under high voltage applications.

Effect of Pulse Electrical Parameters on Performance of Deposited Copper Coatings with Citrate System at Room Temperature

2014 ◽  
Vol 528 ◽  
pp. 8-13
Author(s):  
Jian Jun Xi ◽  
Jun Zhao ◽  
Zhi Gang Wang ◽  
Chun Ping Zhao ◽  
Mei Ping Xue
Keyword(s):  
Surface Morphology ◽  
Current Density ◽  
Coating Thickness ◽  
Room Temperature ◽  
Duty Ratio ◽  
Thickness Gauge ◽  
Copper Plating ◽  
Electrical Parameters ◽  
Uniform Coating ◽  
Copper Coatings

This article presents a detailed research on pulse electrical parameters for non-cyanide electroplating copper plating on stainless still substrate. The study was made about the effect of the current density, duty ratio and frequency on the surface morphology, thickness and uniformity of the deposited layers. The surface morphology was examined by MIT 300 metallurgical microscope and the thickness of copper coatings was examined by TT260 coating thickness gauge. Current density 0.4A/dm2 is the optimum current at which the best uniform coating can be formed.

Effects of Processing Parameters of Oxide Layer in Ultrasonic Vibration and Electrolytic In-Process Dressing Combined Grinding

2014 ◽  
Vol 1027 ◽  
pp. 3-7
Author(s):  
Bo Zhao ◽  
Xiao Feng Jia
Keyword(s):  
Surface Morphology ◽  
Oxide Layer ◽  
Ultrasonic Vibration ◽  
Processing Parameters ◽  
Wheel Speed ◽  
Duty Ratio ◽  
Process Conditions ◽  
Layer Surface ◽  
Electrical Parameters ◽  
Electrode Gap

In order to study the states of oxide layer under different pre-dressing process conditions in ultrasonic vibration and electrolytic in-process dressing combined grinding. The effects of electrical parameters, wheel speed, ultrasonic vibration on the oxide layer are investigated with indicators of oxide layer surface morphology and thickness characteristics. The results indicate that the oxide layer thickness increases with the decrease of inter-electrode gap and the increase of duty ratio with pre-dressing time. The effect of ultrasonic vibration cause thinning of the oxide layer. Oxide layer surface morphology allowing processing requirements are obtained by duty cycle of 5μs: 5μs, electrode gap of 0.3mm, wheel speed of 3200 r/min.

An Established Epithelial Cell Line (NPC/HK1) from a Nasopharyngeal Carcinoma - II. A Sem Study

1982 ◽  
Vol 40 ◽  
pp. 224-225
Author(s):  
Li C.L. ◽  
Chew E.C. ◽  
Huang D.P. ◽  
Ho H.C. ◽  
Mak L.S. ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epithelial Cell ◽  
Surface Morphology ◽  
Cell Line ◽  
Epithelial Cell Line ◽  
Present Communication ◽  
Cells In Culture ◽  
Sem Study ◽  
Well Differentiated

An epithelial cell line, NPC/HK1, has recently been successfully established from a nasopharyngeal carcinoma of the moderately to well differentiated squamous type. The present communication reports on the surface morphology of the NPC/HK1 cells in culture.

Specimen Collection Effect in Scanning Electron Microscopy Images

1972 ◽  
Vol 30 ◽  
pp. 448-449
Author(s):  
J. Temple Black ◽  
Jose Guerrero
Keyword(s):  
Surface Morphology ◽  
Secondary Electron Emission ◽  
Secondary Electrons ◽  
Charge Effects ◽  
Material Density ◽  
Specimen Collection ◽  
The Subject ◽  
Curved Paths ◽  
Subject Material ◽  
Microscopy Images

In the SEM, contrast in the image is the result of variations in the volume secondary electron emission and backscatter emission which reaches the detector and serves to intensity modulate the signal for the CRT's. This emission is a function of the accelerating potential, material density, chemistry, crystallography, local charge effects, surface morphology and especially the angle of the incident electron beam with the particular surface site. Aside from the influence of object inclination, the surface morphology is the most important feature In producing contrast. “Specimen collection“ is the name given the shielding of the collector by adjacent parts of the specimen, producing much image contrast. This type of contrast can occur for both secondary and backscatter electrons even though the secondary electrons take curved paths to the detector-collector.Figure 1 demonstrates, in a unique and striking fashion, the specimen collection effect. The subject material here is Armco Iron, 99.85% purity, which was spark machined.

The Effect of Benzene on Bluegill Olfactory Lamellae

1985 ◽  
Vol 43 ◽  
pp. 574-575
Author(s):  
D.R. Mattie ◽  
J.W. Fisher
Keyword(s):  
Surface Morphology ◽  
Soluble Fraction ◽  
Lepomis Macrochirus ◽  
Sublethal Concentration ◽  
Water Soluble ◽  
Major Constituent ◽  
Jet Fuels ◽  
Aquatic Biota ◽  
Normal Surface ◽  
Cacodylate Buffer

Jet fuels such as JP-4 can be introduced into the environment and come in contact with aquatic biota in several ways. Studies in this laboratory have demonstrated JP-4 toxicity to fish. Benzene is the major constituent of the water soluble fraction of JP-4. The normal surface morphology of bluegill olfactory lamellae was examined in conjunction with electrophysiology experiments. There was no information regarding the ultrastructural and physiological responses of the olfactory epithelium of bluegills to acute benzene exposure.The purpose of this investigation was to determine the effects of benzene on the surface morphology of the nasal rosettes of the bluegill sunfish (Lepomis macrochirus). Bluegills were exposed to a sublethal concentration of 7.7±0.2ppm (+S.E.M.) benzene for five, ten or fourteen days. Nasal rosettes were fixed in 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.1M cacodylate buffer (pH 7.4) containing 1.25mM calcium chloride. Specimens were processed for scanning electron microscopy.

Observation of surface morphology by reflection electron holography

1989 ◽  
Vol 47 ◽  
pp. 536-537
Author(s):  
N. Osakabe ◽  
J. Endo ◽  
T. Matsuda ◽  
A. Tonomura
Keyword(s):  
Phase Shift ◽  
Surface Morphology ◽  
High Sensitivity ◽  
High Energy ◽  
Path Difference ◽  
Transmission Mode ◽  
Electron Holography ◽  
Dynamical Process ◽  
High Vertical Resolution ◽  
Amplification Technique

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.

Defect morphology in thick relaxed layers of InGaAs on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 668-669
Author(s):  
R H Dixon ◽  
P Kidd ◽  
P J Goodhew
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Strained Layers ◽  
Good Surface ◽  
Transmission Electron ◽  
Device Structures ◽  
Surface Morphologies

Thick relaxed InGaAs layers grown epitaxially on GaAs are potentially useful substrates for growing high indium percentage strained layers. It is important that these relaxed layers are defect free and have a good surface morphology for the subsequent growth of device structures.3μm relaxed layers of InxGa1-xAs were grown on semi - insulating GaAs substrates by Molecular Beam Epitaxy (MBE), where the indium composition ranged from x=0.1 to 1.0. The interface, bulk and surface of the layers have been examined in planar view and cross-section by Transmission Electron Microscopy (TEM). The surface morphologies have been characterised by Scanning Electron Microscopy (SEM), and the bulk lattice perfection of the layers assessed using Double Crystal X-ray Diffraction (DCXRD).The surface morphology has been found to correlate with the growth conditions, with the type of defects grown-in to the layer (e.g. stacking faults, microtwins), and with the nature and density of dislocations in the interface.

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