scholarly journals Self-Consistent Calculation of Potential Profile of GaN/AlN Resonace Tunnelling Structures

2017 ◽  
Vol 18 (3) ◽  
pp. 288-296
Author(s):  
I.V. Boyko ◽  
M.V. Tkach ◽  
Ju.O. Seti
Keyword(s):  
Electron Energy Spectrum ◽  
Potential Profile ◽  
System Of Equations ◽  
Poisson System ◽  
Potential Wells ◽  
Potential Barriers ◽  
Quantum Cascade ◽  
Self Consistent ◽  
Dielectric Continuum ◽  
Resonant Tunneling Structure

For resonant tunneling structure with GaN – potential wells and AlN – potential barriers, calculation of internal fields caused by piezoelectric and spontaneous polarization was carried. In the model the effective mass of an electron and a dielectric continuum model using finite difference method self-consistent solutions of the Schrödinger and Poisson system of equations taking into account the contribution of piezoelectric and spontaneous polarizations was found.Based on the found solutions of the Schrödinger and Poisson system of equations for resonance tunneling structure, which functioned as a cascade experimentally realized a quantum cascade detector, calculation of the potential profile and the electron energy spectrum was carried. It was found, that calculated value of detected energy is different from the experimentally obtained not more than 3 %.

scholarly journals Theory of Dynamic Conductivity of Three-Barrier Resonance-Tullel Structure with Two-Photon Laser Transitions

2015 ◽  
Vol 16 (1) ◽  
pp. 7-13
Author(s):  
Ju. O. Seti ◽  
I. V. Boyko ◽  
M. V. Pan’kiv
Keyword(s):  
Potential Wells ◽  
Dynamic Conductivity ◽  
Potential Barriers ◽  
Quantum Cascade ◽  
Two Photon ◽  
Geometric Configurations ◽  
Quantum Transitions ◽  
Electron Quantum ◽  
Different Depths ◽  
Resonant Tunneling Structure

Within the approximation of effective mass and rectangular potential barriers for the electron and using the obtained solutions of complete Schrodinger equation, the theory of dynamic conductivity for three-barrier resonant tunneling structure (InGaAs/InAlAs) with different depths of potential wells driven by weak electromagnetic field is developed in one- and two-photon approach. It is shown that varying Ga concentration one can obtain such geometric configurations of nanostructure, being an active region of quantum cascade laser, in which the increasing intensity of laser radiation, produced by electron quantum transitions accompanied by radiation of two photons with equal energy, is observed. It is established that the contribution of two-photon transitions into the complete magnitude of dynamic conductivity is not smaller than 37 %.

ACCELERATION OF DIFFUSION IN SUBCRITICALLY TILTED PERIODIC POTENTIALS

2005 ◽  
Vol 05 (02) ◽  
pp. L283-L290 ◽  
Author(s):  
NIKOLAY AGUDOV ◽  
ALEXEY SAFONOV
Keyword(s):  
Diffusion Coefficient ◽  
Brownian Particle ◽  
Effective Diffusion ◽  
Potential Profile ◽  
Linear Potential ◽  
Potential Wells ◽  
Potential Barriers ◽  
Periodic Potentials ◽  
Independent Variation ◽  
Shape Of Potential

We study the enhancement of effective diffusion coefficient of an overdamped Brownian particle in tilted periodical potential profile. For analysis we use the model piece-wise linear potential, where independent variation of the potential profile parameters (such as height and width of potential barriers, width of potential wells and period of potential profile) is possible. This approach allows to investigate the influence of potential profile shape on the conditions for the diffusion acceleration, maximal value of the diffusion coefficient, values of noise intensity and the tilt for which the maximum occurs. For the large barriers and subcritical tilt the results are generalized for arbitrary shape of potential profile.

A perturbation method for the Vlasov–Poisson system

1998 ◽  
Vol 60 (1) ◽  
pp. 181-192 ◽  
Author(s):  
JONAS LUNDBERG ◽  
TOR FLÅ
Keyword(s):  
Perturbation Method ◽  
Particle Distribution ◽  
Distribution Functions ◽  
Poisson System ◽  
Nonlinear Wave Propagation ◽  
Starting Point ◽  
Self Consistent ◽  
Good Starting Point ◽  
New Perturbation ◽  
Lie Transformations

A perturbation method for the Vlasov–Poisson system is presented. It is self-consistent and entirely based on Lie transformations, which are considered as active transformations, generating the dynamics of the particle distribution function in the space of distribution functions. The main result is a set of three equations that forms a good starting point for a wide variety of problems concerning nonlinear wave propagation. Besides being efficient, the new perturbation method is systematic and therefore also suited for the use of computer algebra.

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