Hydrogenic impurity binding energy in vertically coupled Ga1-xAlxAs quantum-dots under hydrostatic pressure and applied electric field

2009 ◽  
Vol 404 (23-24) ◽  
pp. 5177-5180 ◽  
Author(s):  
C.M. Duque ◽  
M.G. Barseghyan ◽  
C.A. Duque
Keyword(s):  
Quantum Dots ◽  
Hydrostatic Pressure ◽  
Binding Energy ◽  
Electric Field ◽  
Applied Electric Field ◽  
Hydrogenic Impurity

scholarly journals Barrier Thickness and Hydrostatic Pressure Effects on Hydrogenic Impurity States in Wurtzite GaN/AlxGa1−xN Strained Quantum Dots

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guangxin Wang ◽  
Xiuzhi Duan ◽  
Wei Chen
Keyword(s):  
Quantum Dots ◽  
Hydrostatic Pressure ◽  
Binding Energy ◽  
Effective Mass ◽  
Dielectric Constants ◽  
Pressure Effects ◽  
Physical Parameters ◽  
Barrier Thickness ◽  
Hydrogenic Impurity ◽  
Donor Binding Energy

Within the framework of the effective mass approximation, barrier thickness and hydrostatic pressure effects on the ground-state binding energy of hydrogenic impurity are investigated in wurtzite (WZ) GaN/AlxGa1−xN strained quantum dots (QDs) by means of a variational approach. The hydrostatic pressure dependence of physical parameters such as electron effective mass, energy band gaps, lattice constants, and dielectric constants is considered in the calculations. Numerical results show that the donor binding energy for any impurity position increases when the hydrostatic pressure increases. The donor binding energy for the impurity located at the central of the QD increases firstly and then begins to drop quickly with the decrease of QD radius (height) in strong built-in electric fields. Moreover, the influence of barrier thickness along the QD growth direction and Al concentration on donor binding energy is also investigated. In addition, we also found that impurity positions have great influence on the donor binding energy.

BINDING ENERGIES OF HYDROGENIC IMPURITIES ON-CENTER AND OFF-CENTER IN CYLINDRICAL QUANTUM DOTS UNDER ELECTRIC AND MAGNETIC FIELDS

2010 ◽  
Vol 24 (22) ◽  
pp. 4293-4304 ◽  
Author(s):  
SHENG WANG ◽  
GUOZHU WEI ◽  
GUANGYU YI
Keyword(s):  
Quantum Dots ◽  
Binding Energy ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electric Fields ◽  
Effective Radius ◽  
Binding Energies ◽  
Hydrogenic Impurity ◽  
Lateral Confinement ◽  
Electric And Magnetic Fields

The ground-state binding energies of a hydrogenic impurity in cylindrical quantum dots (QDs) subjected to external electric and magnetic fields are investigated using the finite-difference method within the quasi-one-dimensional effective potential model. The QD is modeled by superposing a square-well potential and a strong lateral confinement potential by the combination of a parabolic potential and a changeable magnetic field. We define an effective radius of a cylindrical QD which can describe the strength of the lateral confinement. The effects of the electric fields are less important when the effective radius is very tiny, and the effects are manifested as the effective radius increases. Meanwhile, one finds that the binding energies highly depend on the impurity positions under the applied transverse fields. When the impurity is located at the right half of the cylinder, the electric field pushes the electron to the left side, then the binding energy decreases; when the impurity is located at the left, the binding energy first increases and reaches a peak value, then deceases with the electric field.

scholarly journals Hydrostatic Pressure and Built-In Electric Field Effects on the Donor Impurity States in Cylindrical Wurtzite GaN/AlxGa1−xN Quantum Rings

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guangxin Wang ◽  
Xiuzhi Duan ◽  
Rui Zhou
Keyword(s):  
Hydrostatic Pressure ◽  
Binding Energy ◽  
Electric Field ◽  
Growth Direction ◽  
Quantum Ring ◽  
Hydrogenic Impurity ◽  
Mass Approximation ◽  
Donor Binding Energy ◽  
Radial Thickness ◽  
Physical Reasons

Within the framework of the effective mass approximation, the ground-state binding energy of a hydrogenic impurity is investigated in cylindrical wurtzite GaN/AlxGa1-xNstrained quantum ring (QR) by means of a variational approach, considering the influence of the applied hydrostatic pressure along the QR growth direction and the strong built-in electric field (BEF) due to the piezoelectricity and spontaneous polarization. Numerical results show that the donor binding energy for a central impurity increases inchmeal firstly as the QR radial thickness(ΔR)decreases gradually and then begins to drop quickly. In addition, the donor binding energy is an increasing (a decreasing) function of the inner radius (height). It is also found that the donor binding energy increases almost linearly with the increment of the applied hydrostatic pressure. Moreover, we also found that impurity positions have an important influence on the donor binding energy. The physical reasons have been analyzed in detail.

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