Effects of magnetic field on the electronic structure of wurtzite quantum dots: Calculations using effective-mass envelope function theory

2005 ◽  
Vol 72 (7) ◽  
Author(s):  
X. W. Zhang ◽  
J. B. Xia
1989 ◽  
Vol 163 ◽  
Author(s):  
A Thilderkvist ◽  
G Grossmann ◽  
M Kleverman ◽  
H G Grimmeiss

AbstractA donor-like spectrum in Fe-doped silicon has been studied by means of high-resolution Zeeman spectroscopy. Previous work had unambigouosly identified the center as the interstitial iron impurity and the spectrum was interpreted as due to the transitions , where an electron is excited to shallow effective-masslike donor states. In this paper, we can, by studying the transitions in a magnetic field, verify the effective-mass-like character of the loosely bound electron. Furthermore, we also obtain information on the impurity core whose level structure is reflected in the observed superposition of donor-hke Rydeberg series and whose g values determines the Zeeman splitting pattern.


2009 ◽  
Vol 23 (26) ◽  
pp. 5109-5118 ◽  
Author(s):  
A. JOHN PETER

The binding energy of shallow hydrogenic impurities in parabolic GaAs/GaAlAs quantum dots is calculated as a function of dot radius in the influence of magnetic field. The binding energy has been calculated following a variational procedure within the effective-mass approximation. Calculations are presented with constant effective-mass and position dependent effective masses. A finite confining potential well with depth is determined by the discontinuity of the band gap in the quantum dot and the cladding. The results show that the impurity binding energy (i) increases as the dot radius decreases for the infinite case, (ii) reaches a peak value around 1R* as the dot radius decreases and then diminishes to a limiting value corresponding to the radius for which there are no bound states in the well for the infinite case, and (iii) increases with the magnetic field. Also it is found that (i) the use of constant effective mass (0.067 m0) is justified for dot sizes ≥ a* where a* is the effective Bohr radius which is about 100 Å for GaAs , in the estimation of ionization energy and (ii) the binding energy shows complicated behavior when the position dependent mass is included for the dot size ≤ a*. These results are compared with the available existing literatures.


2014 ◽  
Vol 895 ◽  
pp. 415-419
Author(s):  
Chin Y. Woon ◽  
Geri Gopir ◽  
Ahmad Puaad Othman

Recently, theoretical analysis of the electronic properties of quantum dot has attracted a great attention when modern nanotechnology has made it possible to fabricate a realistic quantum dots in laboratory [. Quantum dot structures which provide electron confinement in three dimensions can be grown by the so called self-assembly effect or Stranski-Krastanov growth mode. Particular interest attracts ordering effects in StranskiKrastanow growth which proceeds on a lattice-mismatched substrate via formation of essentially three-dimensional islands. This is especially true for the InAs-GaAs system where the lattice mismatch is high and the nucleation process is rapid. Although, quantum dots have being studied experimentally but large amount of numerical studies of electron confined states also have been developed to simulate electronic and optical properties in quantum dots. The single band effective mass is one of the formalism of envelope function which has been widely used to solve quantum dot systems. However, the effective massm*is usually position dependent in semiconductor heterostrutures. Consequently, the concerning about the form of the boundary conditions to impose on different material interface arisen [3]. According to the present works [2, , the position dependent Hamiltonian is given by: . wherem=m(r) is the position dependent effective mass of an electron in conduction band. The constant α, β, and γ is arbitrary set to satisfy α + β + γ = -1. Various approximations regarding the actual constant of α, β, and γ in position dependent effective mass have been observed, example Gora & William (by putting α = -1 and β = γ = 0), Zhu & Kroemer (α = γ = -1/2 and β = 0), and BenDaniel-Duke (α = γ = 0 and β = -1). Among them, β = 1 (known as the Ben DanielDuke Hamiltonian [) is most popular method for solving mass continuity problem on the classic Hamiltonian [. Extensively, these interface condition was been used to solved most of the heterostructure problem such as quantum dots [. However, there is a qualitative argument based upon the Ben DanielDuke choice violates the Heisenberg uncertainty principle and the issue of the correct effective-mass equation was further questioned by Pistol, M. E. which he claims that all the possible equations lead to the same interfacial conditions on the envelope function [. In this paper, we will investigate the effect of discontinuity mass within interface of two semiconductor materials inside InAs-GaAs quantum dot by using the classic constant mass Hamiltonian (CH), position dependent effective mass Hamiltonian (PDH) and Ben Daniel and Duke Hamiltonian (BDH). The most common analytic methods are solving the transcendental equation obtained by matching the interface boundary condition on the envelope function. But this kind of method will suffer from complexity of model quantum dots that contain multiple layer or geometry that unable to derive into analytic formulation. Thus, this study will focus on comparison between difference finite difference formalism to illustrate the mass discontinuity effect on the numerical solution.


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