Carrier motion in as-spun and annealed P3HT:PCBM blends revealed by ultrafast optical electric field probing and Monte Carlo simulations

2014 ◽  
Vol 16 (6) ◽  
pp. 2686 ◽  
Author(s):  
Vytautas Abramavičius ◽  
Dimali Amarasinghe Vithanage ◽  
Andrius Devižis ◽  
Yingyot Infahsaeng ◽  
Annalisa Bruno ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Electric Field ◽  
Monte Carlo Simulations ◽  
Ultrafast Optical

Monte Carlo simulations of zero electric field gradient liquid crystal mixtures

2000 ◽  
Vol 331 (5-6) ◽  
pp. 455-464 ◽  
Author(s):  
E.Elliott Burnell ◽  
Roberto Berardi ◽  
Raymond T. Syvitski ◽  
Claudio Zannoni
Keyword(s):  
Monte Carlo ◽  
Liquid Crystal ◽  
Electric Field ◽  
Monte Carlo Simulations ◽  
Electric Field Gradient ◽  
Field Gradient

INFRARED QUANTUM-DOT DETECTORS WITH DIFFUSION-LIMITED CAPTURE

2007 ◽  
Vol 17 (03) ◽  
pp. 585-591 ◽  
Author(s):  
N. VAGIDOV ◽  
A. SERGEEV ◽  
V. MITIN
Keyword(s):  
Monte Carlo ◽  
Quantum Dot ◽  
Electric Field ◽  
Monte Carlo Simulations ◽  
Room Temperature ◽  
Hot Electrons ◽  
Modulation Doping ◽  
Potential Barriers ◽  
Diffusion Limited ◽  
Transit Times

Employing Monte-Carlo simulations we investigate parameters and optimize geometry of IR quantum-dot detectors with diffusion-limited capture into the dots surrounded by potential barriers. Our results show that structures with modulation doping of interdot matrix provide an effective separation of the localized and conducting electron states. In these structures, the capture time is mainly determined by the quantum dot concentration and the height of potential barriers around dots. The capture is not sensitive to the dot positions. It also weakly depends on the electric field up to the characteristic value, at which significant electron heating allows hot electrons to overcome the barriers. Optimizing the carrier capture and transit times, we show that quantum-dot structures have a lot of potentials for increasing the photoconductive gain and for the development of IR room-temperature detectors.

A Semi-Analytical Interpretation of Transient Electron Transport in Gallium Nitride, Indium Nitride, and Aluminum Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
B. E. Foutz ◽  
S. K. O'Leary ◽  
M. S. Shur ◽  
L. F. Eastman
Keyword(s):  
Monte Carlo ◽  
Gallium Nitride ◽  
Electric Field ◽  
Aluminum Nitride ◽  
Monte Carlo Simulations ◽  
Field Effect Transistors ◽  
Indium Nitride ◽  
Relaxation Times ◽  
Transient Effects ◽  
Energy Dependent

ABSTRACTThe energy dependent momentum and energy relaxation times, and the effective single valley energy dependent effective mass, are extracted from Monte Carlo simulations of gallium nitride, indium nitride, and aluminum nitride. A simple semi-analytical energy model, which uses these dependencies, is in good agreement with the results of transient Monte Carlo simulations. Both the Monte Carlo and the semi-analytical simulations show that the overshoot effects are most pronounced when the electric field abruptly changes from a value below a critical field to one above. This is attributed to the relatively large difference between the effective energy and momentum relaxation times for such a variation of electric field. Our calculations indicate that gallium nitride and indium nitride should have the most pronounced transient effects. A calculation of the transit times as a function of the gate length shows that an upper bound for the maximum expected cut-off frequencies are 260 GHz and 440 GHz for 0.2 μm gallium nitride and indium nitride field effect transistors, respectively.

ELECTRON HEATING IN QUANTUM-DOT STRUCTURES WITH COLLECTIVE POTENTIAL BARRIERS

2011 ◽  
Vol 20 (01) ◽  
pp. 143-152 ◽  
Author(s):  
L.H. CHIEN ◽  
A. SERGEEV ◽  
N. VAGIDOV ◽  
V. MITIN ◽  
S. BIRNER
Keyword(s):  
Quantum Dots ◽  
Monte Carlo ◽  
Quantum Dot ◽  
Electric Field ◽  
Monte Carlo Simulations ◽  
Electric Fields ◽  
Geometrical Parameters ◽  
Electron Heating ◽  
Potential Barriers ◽  
Strong Electric Fields

Here we report our research on quantum-dot structures with collective barriers surrounding groups of quantum dots (planes, clusters etc) and preventing photoelectron capture. Employing Monte-Carlo simulations, we investigate photoelectron kinetics and calculate the photoelectron lifetime as a function of geometrical parameters of the structures, dot occupation, and electric field. Results of our simulations demonstrate that the capture processes are substantially suppressed by the potential barriers and enhanced in strong electric fields. Detailed analysis shows that the effects of the electric field can be explained by electron heating, i.e. field effects become significant, when the shift of the electron temperature due to electron heating reaches the barrier height. Optimized photoelectron kinetics in quantum-dot structures with collective barriers allows for significant improvements in the photoconductive gain, detectivity, and responsivity of photodetectors based on these structures.

SIMULATIONS OF RADIO EMISSION FROM ELECTROMAGNETIC SHOWERS IN DENSE MEDIA

2006 ◽  
Vol 21 (supp01) ◽  
pp. 55-59 ◽  
Author(s):  
J. ALVAREZ-MUÑIZ ◽  
E. MARQUES ◽  
R. A. VAZQUEZ ◽  
E. ZAS
Keyword(s):  
Monte Carlo ◽  
Simple Model ◽  
Radio Emission ◽  
Electric Field ◽  
Monte Carlo Simulations ◽  
Scaling Behavior ◽  
Excess Charge ◽  
Electromagnetic Showers ◽  
Field Spectrum ◽  
Dense Media

By means of GEANT4-based Monte Carlo simulations, we have studied the frequency and angular behavior of Cherenkov radio pulses originated by the excess charge in electromagnetic (EM) showers in different dense media. We have developed a simple model to relate the main characteristics of the electric field spectrum to the longitudinal and lateral development of the EM showers. Using this model the electric field spectrum is shown to have a scaling behavior with a number of medium parameters. We explore the validity of our model by comparing its predictions against full Monte Carlo simulations.

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