Barrier Limited Transport Mechanisms in Doped μc-Si and μc-Si,C

1991 ◽  
Vol 219 ◽  
Author(s):  
G. Lucovsky ◽  
C. Wang
Keyword(s):  
Room Temperature ◽  
Thermionic Emission ◽  
Activation Energies ◽  
High Conductivity ◽  
Band Alignment ◽  
Optical Transparency ◽  
Transport Mechanisms ◽  
Potential Barriers ◽  
Alignment Model ◽  
Interfacial Potential

ABSTRACTAn analysis of the room-temperature dark conductivities and activation energies for doped μc-Si and μc-Si,C is used to develop a band alignment model which shows that the maximum attainable dark conductivities in these materials are determined by transport through, or over interfacial potential barriers between Si crystallites, c-Si, and the intervening amorphous regions: a-Si:H or a-Si,C:H, respectively. For all levels of doping in μc-Si,C, the transport is limited by thermionic emission over interfacial barriers at the c-Si/a-Si,C:H interface, placing a significant constraint on applications requiring both high optical transparency and high conductivity.

GaAs/InGaAs Optoelectronic Switch for Triple-Logic Applications

2012 ◽  
Vol 459 ◽  
pp. 40-43
Author(s):  
Kao Feng Yarn ◽  
Ming Ju Yang ◽  
Wen Chung Chang
Keyword(s):  
Circuit Design ◽  
Room Temperature ◽  
Thermionic Emission ◽  
Differential Resistance ◽  
Switching Voltage ◽  
State Characteristic ◽  
Potential Barriers ◽  
Load Line ◽  
Hole Confinement ◽  
Optoelectronic Switch

A new GaAs/InGaAs triangular barrier optoelectronic switch combined with tri-state characteristic is fabricated and demonstrated. Two GaAs/InGaAs barriers are employed to provide potential barriers for electron thermionic emission and hole confinement, respectively. Applying a sufficient DC voltage to this device, a double S-shaped negative differential resistance (NDR) phenomenon with nearly equal switching voltage difference is appeared at room temperature. This unique NDR property can be introduced to triple stable regions into the device circuit design. Based on a proper circuit design with suitable load line, the studied device has potential for triple-logic applications.

Electron Transport Mechanisms in Nickel Schottky Barrier Contacts to Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
D.E. Heller ◽  
M. Gunes ◽  
F. Rubinelli ◽  
R.M. Dawson ◽  
S. Nag ◽  
...  
Keyword(s):  
Electron Transport ◽  
Room Temperature ◽  
Schottky Diodes ◽  
Diffusion Mechanism ◽  
Thermionic Emission ◽  
Transport Mechanisms ◽  
Drift Diffusion ◽  
Accurate Picture ◽  
Hydrogenated Amorphous ◽  
Best Fit

ABSTRACTDark J-V characteristics of Ni Schottky diodes on a-Si:H films of various thicknesses were measured as a function of device temperature. Room-temperature photoconductivity and sub-bandgap absorption v. wavelength measurements of the intrinsic layers were also performed. Detailed numerical modelling was employed to determine the nature, density and energy distribution of sub- bandgap states. Best-fit modelling of photoconductivity, sub-bandgap absorption and dark JR-VR indicates that Nc=Nv=2.5×1020 cm-3, vR=2×106 cm/s, μn=33 cm2/V-s and μp=0.15 cm2/V-s for these films. It is found that a joint thermionic emission-drift/diffusion mechanism, as envisaged by Crowell and Sze, appears to be the most accurate picture of electron transport in Schottky diodes on intrinsic a-Si:H films.

Thermooxidative Aging Studies on Silicone Rubber and Lifetime Prediction

2013 ◽  
Vol 777 ◽  
pp. 11-14
Author(s):  
You Shan Wang ◽  
Sha Sha Jiang ◽  
Yu Peng Liu
Keyword(s):  
Silicone Rubber ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Activation Energies ◽  
Lifetime Prediction ◽  
Arrhenius Behavior ◽  
Compression Set ◽  
Degradation Processes ◽  
Aging Studies ◽  
Significant Compression

Silicone rubber have been aged in air while under 25% compression at temperature up to 250°C. These studies examined the compression set of silicone rubber at accelerated (elevated) temperatures and were then used to make predictions about compression set at room temperature. The data obtained could be amenable to timetemperature superposition and Arrhenius treatment. The results suggest the presence of two degradation processes with activation energies of 71.6 kJ mol-1 (for temperatures above 165 °C) and 26.08 kJ mol-1 (for temperatures below 165 °C). Based on the extrapolation of the non-Arrhenius behavior, it was estimated that significant compression set loss would occur after around 67 years at 25 °C.

Electrical Properties of Nanostructure n-ZnSe/p-Si(100) Heterojunction Thin Film Diode

2018 ◽  
Vol 775 ◽  
pp. 246-253
Author(s):  
Ngamnit Wongcharoen ◽  
Thitinai Gaewdang
Keyword(s):  
Thin Films ◽  
Ideality Factor ◽  
Room Temperature ◽  
Energy Levels ◽  
Thermionic Emission ◽  
Depletion Region ◽  
Trap Level ◽  
Characteristic Energy ◽  
Znse Thin Films

The ZnSe/Si heterojunction is of specific interest since this structure provides effective solar cell and enables the integration of wide bandgap device in silicon circuits. It is known that the quality of the diode and the current transport mechanisms across the heterojunction may be greatly influenced by the quality of the interface and depends on the crystallinity of the film layer. In this work, n-ZnSe/p-Si (100) heterojunction was fabricated by thermal evaporating ZnSe thin films on p-Si (100) substrates. The current-voltage characteristics of n-ZnSe/p-Si (100) heterojunction were investigated in temperature range 20-300 K. Some important parameters such as barrier height, ideality factor and series resistance values evaluated by using thermionic emission (TE) theory and Cheung’s method at room temperature are n = 2.910,φB0= 0.832 eV and 8.59103Ω, respectively. The temperature dependence of the saturation current and ideality factor are well described by tunneling enhanced recombination at junction interface with activation energy and characteristic energy values about 1.293 eV and E00= 95 meV, respectively. The carrier concentration of ZnSe thin films about 3.16×1013cm-3was deduced from the C-V measurements at room temperature. Admittance spectroscopy was employed for analysis of the defect energy levels situated in depletion region. The results showed that there was a single trap level whose position in the band gap was close to 0.04 eV above valence band. The results of this work may be useful for application such as heterojunction solar cells.

scholarly journals Phonon hydrodynamics and ultrahigh–room-temperature thermal conductivity in thin graphite

Science ◽  
2020 ◽  
Vol 367 (6475) ◽  
pp. 309-312 ◽  
Author(s):  
Yo Machida ◽  
Nayuta Matsumoto ◽  
Takayuki Isono ◽  
Kamran Behnia
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Phonon Dispersion ◽  
High Conductivity ◽  
Temperature Range ◽  
A Value ◽  
Out Of Plane ◽  
Intimate Link

Allotropes of carbon, such as diamond and graphene, are among the best conductors of heat. We monitored the evolution of thermal conductivity in thin graphite as a function of temperature and thickness and found an intimate link between high conductivity, thickness, and phonon hydrodynamics. The room-temperature in-plane thermal conductivity of 8.5-micrometer-thick graphite was 4300 watts per meter-kelvin—a value well above that for diamond and slightly larger than in isotopically purified graphene. Warming enhances thermal diffusivity across a wide temperature range, supporting partially hydrodynamic phonon flow. The enhancement of thermal conductivity that we observed with decreasing thickness points to a correlation between the out-of-plane momentum of phonons and the fraction of momentum-relaxing collisions. We argue that this is due to the extreme phonon dispersion anisotropy in graphite.

Syntheses and Investigation of Properties of New Ionic Liquids Thiazolium Halogenide

2011 ◽  
Vol 332-334 ◽  
pp. 2036-2039 ◽  
Author(s):  
Qing Kai Wang ◽  
Hong Jun Zang ◽  
Fang Yang ◽  
Bo Wen Cheng ◽  
Yuan Lin Ren ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
1H Nmr ◽  
Elemental Analysis ◽  
Room Temperature ◽  
High Conductivity ◽  
Room Temperature Ionic Liquids ◽  
Melting Points ◽  
Polar Solvents ◽  
Good Solubility

A series of novel thiazolium halogenide ionic liquids were synthesized by using 4-methylthiazole or 4-methyl-5-thiazoleethanol and halohydrocarbons as materials. The compounds were characterized and analyzed by elemental analysis, 1H NMR and DSC.The solubilities of the ionic liquids in organic dissolvents were observed, meanwhile the conductivities and melting points were measured. The results show that these ionic liquids have high conductivity in water and have good solubility in traditional polar solvents, such as H2O, ethanol and acetonitrile. And the thiazolium halogenide are room temperature ionic liquids, due to their low melting points.

Iodine-doped sulfurized polyacrylonitrile with enhanced electrochemical performance for room-temperature sodium/potassium sulfur batteries

2019 ◽  
Vol 55 (36) ◽  
pp. 5267-5270 ◽  
Author(s):  
Shaobo Ma ◽  
Pengjian Zuo ◽  
Han Zhang ◽  
Zhenjiang Yu ◽  
Can Cui ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Room Temperature ◽  
High Conductivity ◽  
Sodium Potassium ◽  
Enhanced Electrochemical Performance

Iodine-doped sulfurized polyacrylonitrile with high conductivity displays an unprecedented capacity for RT-Na/S and RT-K/S batteries operated in ester-based electrolytes.

scholarly journals Negative Differential Resistance Behavior in Delta-Doped AlInP Structure Grown by MOCVD

2002 ◽  
Vol 25 (3) ◽  
pp. 245-248
Author(s):  
K. F. Yarn
Keyword(s):  
Schottky Diode ◽  
Negative Differential Resistance ◽  
Room Temperature ◽  
Thermionic Emission ◽  
Differential Resistance ◽  
Tunneling Effect ◽  
Peak Current Density ◽  
Interband Tunneling ◽  
First Time ◽  
Peak To Valley Ratio

An AlInP delta-doped schottky diode exhibiting negative differential resistance (NDR) behavior is demonstrated for the first time. The NDR characteristics with a peak to valley ratio of 5.5 and peak current density of1KA/cm2were achieved at room temperature. In addition, the maximum available power is estimated up to5W/cm2. The mechanism for such performance is phenomenologically analyzed by the combination of resonant interband tunneling (RIT) and thermionic emission processes associated with tunneling effect on the metal-semiconductor (MS) interface.

Radiation-Sensitized Thermal Cracking of n-Butane. II. Ionic Reactions

1975 ◽  
Vol 53 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Shingo Matsuoka ◽  
Takaaki Tamura ◽  
Keichi Oshima ◽  
Yunosuke Oshima
Keyword(s):  
Room Temperature ◽  
Material Balance ◽  
Thermal Cracking ◽  
Activation Energies ◽  
Chain Reactions ◽  
Ionic Reactions ◽  
Cracking Mechanism ◽  
High Yields ◽  
Increasing Temperature ◽  
First Time

Ionic reactions in the radiolysis of n-butane were studied at temperatures ranging from 17 to 548 °C. Ionic chain reactions were found for the first time to take part in the radiation-sensitized thermal cracking mechanism of hydrocarbon system.The isobutane and isobutene yields increased with increasing temperature and at 548 °C their G-values reached 31.2 and 12.1, respectively, though they were not formed by the thermal cracking of n-butane. The formation was completely suppressed by the addition of 0.15 mol% ammonia. They were produced with high yields irrespective of the kind of wall of the irradiation cells. It was concluded from these results that isobutane and isobutene were formed by homogeneous ionic chain reactions with activation energies. Part of the propane product was also found to have been formed by ionic chain reactions. From the effect of adding n-pentane on the yields of the ionic products, C4H9+ ion was inferred as the carrier ion.In the vicinity of room temperature, formation by ionic reactions of polymers with more than 14 carbon atoms was inferred from the material balance of the products from H2 to C14.

Irregular Electron Transport Through a-Si:H Based Potential Barriers

1993 ◽  
Vol 297 ◽  
Author(s):  
Norbert Bernhard ◽  
B. Frank ◽  
B. Movaghar ◽  
G.H. Bauer
Keyword(s):  
Electron Transport ◽  
Transport Mechanism ◽  
Current Transport ◽  
Transport Mechanisms ◽  
Potential Barriers ◽  
Resonant Tunnelling ◽  
Current Voltage ◽  
Different Temperatures ◽  
Current Voltage Characteristics ◽  
Stable Formation

Irregularities in the current-voltage-characteristics of a-Si:H based potential barriers have been investigated experimentally, and are discussed theoretically with respect to different transport mechanisms. The investigated samples were different series of double and single barrier a-Si:H - a-Si1-xCx:H - heterostructures, as well as homogeneous samples without heterostructure barrier. Current-voltage-(I-V)-characteristics showing a wide variety of features, from complete smoothness of the curves, to bumps and even accidental step-like switching behaviour, as well as different forms of noise, were recorded at different temperatures. Resonant tunnelling as an explaining transport mechanism for the anomalies was excluded because of inconsistency between experiment and calculations partially including special amorphous features. Instead it is argued that all observed irregularities, i. e. bumps in I-V-curves, switching-like behaviour, and appearance of noise, are related to current transport via trap-assisted tunnelling through locally strongly confined transport paths, leading to the meta-stable formation, change and break-down of conductory filaments.

Sign in / Sign up

Export Citation Format

Share Document