Modeling of Polysilicon Resistors, P-N Junction Diodes and Mosfet's

1984 ◽  
Vol 33 ◽  
Author(s):  
A. N. Khondker ◽  
S. S. Ahmed ◽  
T. Liou ◽  
D. M. Kim
Keyword(s):  
Carrier Lifetime ◽  
Current Flow ◽  
Dopant Concentration ◽  
High Current ◽  
Ohmic Conduction ◽  
Direction Parallel ◽  
Mos Devices ◽  
Wide Range ◽  
Conduction Channel ◽  
Channel Region

ABSTRACTConductivity in bulk polysilicon is discussed, applicable over a wide range of dopant concentration, temperature, grain size and trap density. The I-V behavior in a lateral poly p-n junction is analytically modeled, incorporating the effects of carrier lifetime operative in crystalline grain and amorphous conducting boundary. In particular, the extremely short carrier lifetime within the grain boundary is shown to provide an ohmic conduction channel in a direction parallel to current flow. This ohmic current can account for the unusually high current levels observed at small applied voltages. Also, the shift of the threshold voltage of MOS devices, as influenced by grain traps near the channel region, is analysed.

scholarly journals A Slot-Die Technique for the Preparation of Continuous, High-Area, Chitosan-Based Thin Films

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1566
Author(s):  
Oliver J. Pemble ◽  
Maria Bardosova ◽  
Ian M. Povey ◽  
Martyn E. Pemble
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
High Volume ◽  
Mechanical Anisotropy ◽  
Diverse Range ◽  
Direction Parallel ◽  
High Area ◽  
Wide Range ◽  
Slot Die ◽  
Potential Applications

Chitosan-based films have a diverse range of potential applications but are currently limited in terms of commercial use due to a lack of methods specifically designed to produce thin films in high volumes. To address this limitation directly, hydrogels prepared from chitosan, chitosan-tetraethoxy silane, also known as tetraethyl orthosilicate (TEOS) and chitosan-glutaraldehyde have been used to prepare continuous thin films using a slot-die technique which is described in detail. By way of preliminary analysis of the resulting films for comparison purposes with films made by other methods, the mechanical strength of the films produced was assessed. It was found that as expected, the hybrid films made with TEOS and glutaraldehyde both show a higher yield strength than the films made with chitosan alone. In all cases, the mechanical properties of the films were found to compare very favorably with similar measurements reported in the literature. In order to assess the possible influence of the direction in which the hydrogel passes through the slot-die on the mechanical properties of the films, testing was performed on plain chitosan samples cut in a direction parallel to the direction of travel and perpendicular to this direction. It was found that there was no evidence of any mechanical anisotropy induced by the slot die process. The examples presented here serve to illustrate how the slot-die approach may be used to create high-volume, high-area chitosan-based films cheaply and rapidly. It is suggested that an approach of the type described here may facilitate the use of chitosan-based films for a wide range of important applications.

scholarly journals Origin of long lifetime of band-edge charge carriers in organic–inorganic lead iodide perovskites

2017 ◽  
Vol 114 (29) ◽  
pp. 7519-7524 ◽  
Author(s):  
Tianran Chen ◽  
Wei-Liang Chen ◽  
Benjamin J. Foley ◽  
Jooseop Lee ◽  
Jacob P. C. Ruff ◽  
...  
Keyword(s):  
High Performance ◽  
Carrier Lifetime ◽  
Charge Carriers ◽  
Band Edge ◽  
Lead Iodide ◽  
Solar Cell Performance ◽  
Photovoltaic Materials ◽  
Wide Range ◽  
Long Lifetime ◽  
Photon Recycling

Long carrier lifetime is what makes hybrid organic–inorganic perovskites high-performance photovoltaic materials. Several microscopic mechanisms behind the unusually long carrier lifetime have been proposed, such as formation of large polarons, Rashba effect, ferroelectric domains, and photon recycling. Here, we show that the screening of band-edge charge carriers by rotation of organic cation molecules can be a major contribution to the prolonged carrier lifetime. Our results reveal that the band-edge carrier lifetime increases when the system enters from a phase with lower rotational entropy to another phase with higher entropy. These results imply that the recombination of the photoexcited electrons and holes is suppressed by the screening, leading to the formation of polarons and thereby extending the lifetime. Thus, searching for organic–inorganic perovskites with high rotational entropy over a wide range of temperature may be a key to achieve superior solar cell performance.

Electrode conduction processes in air plasmas

1962 ◽  
Vol 13 (3) ◽  
pp. 465-477 ◽  
Author(s):  
D. W. George ◽  
H. K. Messerle
Keyword(s):  
Magnetic Field ◽  
Shock Tube ◽  
Current Flow ◽  
Electronic Conductivity ◽  
The Other ◽  
High Current ◽  
Air Plasma ◽  
Air Plasmas ◽  
Current Densities

Using an electrically driven shock tube with initial pressures of 0.1 to 1.0 mm Hg and shock speeds of about Mach 12 to 15, the resistance of an air plasma between two parallel probes has been measured by two different techniques and the results compared. In one, external voltages of from 0 to 100 V were applied to the probes and in the other, electromagnetically induced voltages of from 0 to 25 V were produced by the plasma's motion in a magnetic field of up to 3500 G. In either case the resistance was found to decrease as the current flow increased and was consistent with the equilibrium electronic conductivity of the air plasma at high current densities.

Surface characterization of sputtered N:TiO2 thin films within a wide range of dopant concentration

2014 ◽  
Vol 40 (7) ◽  
pp. 9989-9995 ◽  
Author(s):  
A.V. Manole ◽  
M. Dobromir ◽  
R. Apetrei ◽  
V. Nica ◽  
D. Luca
Keyword(s):  
Thin Films ◽  
Surface Characterization ◽  
Dopant Concentration ◽  
Wide Range

scholarly journals Measuring Hall viscosity of graphene’s electron fluid

Science ◽  
2019 ◽  
pp. eaau0685 ◽  
Author(s):  
A. I. Berdyugin ◽  
S. G. Xu ◽  
F. M. D. Pellegrino ◽  
R. Krishna Kumar ◽  
A. Principi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Transport Coefficient ◽  
Current Flow ◽  
High Viscosity ◽  
Electron Systems ◽  
Electrical Conductor ◽  
Electron Fluid ◽  
Wide Range ◽  
Hall Viscosity

An electrical conductor subjected to a magnetic field exhibits the Hall effect in the presence of current flow. Here we report a qualitative deviation from the standard behavior in electron systems with high viscosity. We find that the viscous electron fluid in graphene responds to non-quantizing magnetic fields by producing an electric field opposite to that generated by the ordinary Hall effect. The viscous contribution is substantial and identified by studying local voltages that arise in the vicinity of current-injecting contacts. We analyze the anomaly over a wide range of temperatures and carrier densities and extract the Hall viscosity, a dissipationless transport coefficient that was long identified theoretically but remained elusive in experiments.

scholarly journals Identifying the cause of thermal droop in GaInN-based LEDs by carrier- and thermo-dynamics analysis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dong-Pyo Han ◽  
Gyeong Won Lee ◽  
Sangjin Min ◽  
Dong-Soo Shin ◽  
Jong-In Shim ◽  
...  
Keyword(s):  
Carrier Lifetime ◽  
Complex Dynamics ◽  
Physical Factor ◽  
Physical Factors ◽  
Temperature Dependent ◽  
Light Emitting ◽  
Carrier Lifetimes ◽  
Driving Current ◽  
Wide Range ◽  
Thermal Droop

Abstract This study aims to elucidate the carrier dynamics behind thermal droop in GaInN-based blue light-emitting diodes (LEDs) by separating multiple physical factors. To this end, first, we study the differential carrier lifetimes (DCLs) by measuring the impedance of a sample LED under given driving-current conditions over a very wide operating temperature range of 300 K–500 K. The measured DCLs are decoupled into radiative carrier lifetime (τR) and nonradiative carrier lifetime (τNR), via utilization of the experimental DCL data, and then very carefully investigated as a function of driving current over a wide range of operating temperatures. Next, to understand the measurement results of temperature-dependent τR and τNR characteristics, thermodynamic analysis is conducted, which enables to look deeply into the temperature-dependent behavior of the carriers. On the basis of the results, we reveal that thermal droop is originated by the complex dynamics of multiple closely interrelated physical factors instead of a single physical factor. In particular, we discuss the inherent cause of accelerated thermal droop with elevated temperature.

High Current Drive in Ultra-Short Impact Ionization MOS (I-MOS) Devices

2006 ◽  
Author(s):  
C. Charbuillet ◽  
S. Monfray ◽  
E. Dubois ◽  
P. Bouillon ◽  
F. Judong ◽  
...  
Keyword(s):  
Impact Ionization ◽  
Current Drive ◽  
High Current ◽  
Mos Devices

SIMULATION OF HIGH CURRENT FIELD EMISSION FROM VERTICALLY WELL-ALIGNED METALLIC CARBON NANOTUBES

2004 ◽  
Vol 03 (04n05) ◽  
pp. 677-684 ◽  
Author(s):  
W. S. KOH ◽  
L. K. ANG
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Field Enhancement ◽  
Smooth Transition ◽  
High Current ◽  
Simulation Code ◽  
Particle In Cell ◽  
Current Regime ◽  
Wide Range ◽  
Cell Simulation

We have studied the intense electron beams emitted from multiple metallic, vertical and well-aligned Carbon Nanotube (CNT) field emitters. A two-dimensional (2D) particle-in-cell simulation code MAGIC2D is used to obtain the I–V characteristics near to the apex of the emitters' surface for a given applied electric field and field enhancement factor over a wide range of parameters. The effects of electron space charge and electric field shielding from neighboring emitters are compared in low current and high current regimes. It is found that the electron space charge is dominant in high current regime, where the Fowler–Nordheim (FN) law becomes the 2D Child–Langmuir (CL) law. The emitter spacing, number of emitters, and emitter's uniformity are also particularly studied, and they are more critical in low current regime. Smooth transition from the FN law to CL law is demonstrated.

Study of High Temperature Microwave Annealing on the Performance of 4H-SiC MOS Capacitors

2012 ◽  
Vol 717-720 ◽  
pp. 769-772
Author(s):  
Harsh Naik ◽  
Z. Li ◽  
H. Issa ◽  
Y.L. Tian ◽  
T. Paul Chow
Keyword(s):  
High Temperature ◽  
Covalent Bond ◽  
Attractive Alternative ◽  
Mos Capacitors ◽  
Microwave Annealing ◽  
Annealing Conditions ◽  
Mos Devices ◽  
Strong Covalent Bond ◽  
Post Implantation ◽  
Channel Region

The strong covalent bond of SiC imposes harsh post implantation annealing condition requirement for SiC MOS devices. As a consequence the effect of the annealing conditions on the channel region of the MOS devices becomes critical. High temperature microwave annealing has been shown to be an attractive alternative to conventional thermal annealing techniques. The effect of high temperature rapid microwave annealing on the performance of 4H-SiC MOS capacitors has been studied in this paper. Annealing temperatures ranging from 1600°C up to 2000°C for 30secs is used and the effect of annealing conditions is studied via C-V measurements on MOS capacitors.

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