Effect of geometry on the pressure induced donor binding energy in semiconductor nanostructures

2015 ◽  
Vol 04 (03) ◽  
pp. 1550018
Author(s):  
P. Kalpana ◽  
K. Jayakumar ◽  
P. Nithiananthi
Keyword(s):  
Binding Energy ◽  
External Pressure ◽  
Semiconductor Nanostructures ◽  
Mass Approximation ◽  
Hydrogenic Donor Impurity ◽  
Donor Binding Energy ◽  
X Band ◽  
Hydrogenic Donor ◽  
Band Mixing ◽  
Geometrical Effects

The effect of geometry on an on-center hydrogenic donor impurity in a GaAs /( Ga,Al ) As quantum wire (QWW) and quantum dot (QD) under the influence of Γ–X band mixing due to an applied hydrostatic pressure is theoretically studied. Numerical calculations are performed in an effective mass approximation. The ground state impurity energy is obtained by variational procedure. Both the effects of pressure and geometry are to exert an additional confinement on the impurity inside the wire as well as dot. We found that the donor binding energy is modified by the geometrical effects as well as by the confining potential when it is subjected to external pressure. The results are presented and discussed.

INFLUENCE OF PRESSURE ON THE DIAMAGNETIC SUSCEPTIBILITY OF HYDROGENIC DONOR IN SOME LOW-LYING EXCITED STATES IN A QUANTUM WELL

2007 ◽  
Vol 06 (01) ◽  
pp. 37-40 ◽  
Author(s):  
P. NITHIANANTHI ◽  
K. JAYAKUMAR
Keyword(s):  
Hydrostatic Pressure ◽  
Quantum Well ◽  
Effective Mass ◽  
Excited States ◽  
Diamagnetic Susceptibility ◽  
Mass Approximation ◽  
X Band ◽  
Hydrogenic Donor ◽  
Band Mixing ◽  
Band Crossing

The influence of Γ–X band crossing due to the applied hydrostatic pressure on the diamagnetic susceptibility (χ dia ) of a donor in low-lying excited states like 2s, 2p0, 2p± in a GaAs / Al x Ga 1-x As Quantum Well has been investigated in the effective mass approximation by considering the nonparabolicity of the conduction band. We notice that the effect of Γ–X band mixing is significant on χ dia of a donor lying in excited states. Moreover, the effect of non-parabolicity on χ dia is also predominant for lower well width region. The results are presented and discussed.

EXTERNAL ELECTRIC FIELD EFFECT ON THE HYDROGENIC DONOR IMPURITY IN ZINC-BLENDE GaN/AlGaN CYLINDRICAL QUANTUM WELL WIRE

2010 ◽  
Vol 24 (23) ◽  
pp. 2413-2421 ◽  
Author(s):  
LIMING JIANG ◽  
JIANMENG SUN
Keyword(s):  
Binding Energy ◽  
Electric Field ◽  
External Electric Field ◽  
Stark Shift ◽  
Donor Impurity ◽  
Zinc Blende ◽  
Hydrogenic Donor Impurity ◽  
Donor Binding Energy ◽  
Quantum Well Wire ◽  
Hydrogenic Donor

The binding energy of a hydrogenic donor impurity in a zinc-blende GaN / AlGaN cylindrical quantum well wire (QWW) is calculated in the framework of effective-mass envelope-function theory using the plane wave basis. It is shown that the donor binding energy is highly dependent on the impurity position, the radius of the wire and the external electric field. In addition, Stark shift dependence on the radius of the QWW and the external electric field is also calculated. The donor binding energy has a maximum when the impurity is located at the center of the QWW. The donor binding energy decreases with the increase of the external electric field, but stark shift increases with the increase of the external electric field or the radius of the QWW.

scholarly journals Hydrogenic-Donor Impurity Binding Energy Dependence of the Electric Field in GaAs/AlxGa1−xAs Quantum Rings

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Guangxin Wang ◽  
Xiuzhi Duan ◽  
Wei Chen
Keyword(s):  
Wave Function ◽  
Binding Energy ◽  
Electric Field ◽  
Applied Electric Field ◽  
Donor Impurity ◽  
Electronic Wave ◽  
Hydrogenic Donor Impurity ◽  
Hydrogenic Donor ◽  
Electronic Wave Function ◽  
Radial Thickness

Using a variational method with two-parameter trial wave function and the effective mass approximation, the binding energy of a donor impurity in GaAs/AlxGa1−xAs cylindrical quantum ring (QR) subjected to an external field is calculated. It is shown that the donor impurity binding energy is highly dependent on the QR structure parameters (radial thickness and height), impurity position, and external electric field. The binding energy increases inchmeal as the QR parameters (radial thickness and height) decrease until a maximum value for a central impurity and then begins to drop quickly. The applied electric field can significantly modify the spread of electronic wave function in the QR and shift electronic wave function from the donor position and then leads to binding energy changes. In addition, results for the binding energies of a hydrogenic donor impurity as functions of the impurity position and applied electric field are also presented.

Influence of Al Composition on Donor Impurity States in Self-Formed GaAs-AlxGa1-xAs Quantum Rings

2013 ◽  
Vol 380-384 ◽  
pp. 4284-4289
Author(s):  
Guang Xin Wang ◽  
Xiu Zhi Duan
Keyword(s):  
Binding Energy ◽  
Electric Field ◽  
Growth Direction ◽  
Uniform Electric Field ◽  
Donor Impurity ◽  
Impurity States ◽  
Quantum Rings ◽  
Mass Approximation ◽  
Donor Binding Energy ◽  
Special Value

Based on the the effective mass approximation and variational approach, the donor impurity states confined in self-formed GaAs/AlxGa1-xAs quantum rings (QRs) are investigated theoretically. A uniform electric field is applied along the growth direction of the QR. The different effective masses in the different regions of the GaAs/AlxGa1-xAs QR are taken into consideration. Numerical results show that the binding energy of a donor impurity increases gradually, reaches a maximum value, and then decreases quickly to the special value as the QR height decreases. Given a fixed QR size, the binding energy increases for the impurity located at the center of the QR when the Al composition increases. In addition, it can also be found that when the applied electric field strength increases, the donor binding energy increases for impurities localized at the negative z axis of the QR; however, the donor binding energy decreases slightly for impurities located at the center and positive z axis of the QR.

Magnetic Field Effect on the Binding Energy of a Hydrogenic Donor Impurity in Cylindrical Quantum Ring

2013 ◽  
Vol 380-384 ◽  
pp. 4841-4844 ◽  
Author(s):  
Guang Xin Wang ◽  
Xiu Zhi Duan
Keyword(s):  
Magnetic Field ◽  
Binding Energy ◽  
Magnetic Field Effect ◽  
Internal Surface ◽  
Outer Radius ◽  
Quantum Ring ◽  
Donor Impurity ◽  
Hydrogenic Donor Impurity ◽  
Inner Radius ◽  
Hydrogenic Donor

The binding energy of a hydrogenic donor impurity in cylindrical GaAs quantum ring (QR) subjected to an external magnetic field is calculated within the effect mass approximation using variational method. The binding energy as a function of the QR size (the inner radius, the outer radius), the impurity position and the applied magnetic field is investigated. The results demonstrate that the ground state binding energy behaves as an decreasing function of the outer radius, and the magnetic field. Likewise, the binding energy is an increasing function of the inner radius. The binding energy firstly increases and then decreases with shifting the impurity ion from the internal surface of the QR to the external surface, indicating that there is a maximum.

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