HYDROGENIC IMPURITY STATES IN WURTZITE ZnO/MgZnO QUANTUM DOT

2010 ◽  
Vol 24 (28) ◽  
pp. 2793-2801
Author(s):  
ZAIPING ZENG ◽  
SHUYI WEI ◽  
JINGBO WEI
Keyword(s):  
Binding Energy ◽  
Quantum Dot ◽  
Electric Field ◽  
Ground State ◽  
Asymmetric Distribution ◽  
Electric Field Effect ◽  
Hydrogenic Impurity ◽  
Mass Approximation ◽  
Donor Binding Energy ◽  
The Right

Based on the effective-mass approximation, considering the built-in electric field effect due to the spontaneous and piezoelectric polarizations, the ground-state donor binding energy of a hygrogenic impurity in a cylindrical wurzite (WZ) ZnO / MgZnO strained quantum dot (QD) is investigated variationally. Numerical results show that the ground-state donor binding energy is highly dependent on the Mg composition, the impurity positions and the QD size. The built-in electric field also induces an asymmetric distribution of the ground-state donor binding energy with respect to the center of the QD. In particular, it is found that the ground-state donor binding energy is insensible to the dot height when the impurity is located at the right boundary of the WZ ZnO / MgZnO strained QD if the dot height is large.

THE EFFECTS OF QUANTUM CONFINEMENT ON THE BINDING ENERGY OF HYDROGENIC IMPURITIES IN A SPHERICAL QUANTUM DOT

2006 ◽  
Vol 20 (18) ◽  
pp. 1127-1134 ◽  
Author(s):  
A. JOHN PETER
Keyword(s):  
Binding Energy ◽  
Quantum Dot ◽  
Shallow Donor ◽  
Donor Impurity ◽  
Hydrogenic Impurity ◽  
Spherical Quantum Dot ◽  
Impurity Position ◽  
Mass Approximation ◽  
Donor Binding Energy ◽  
Parabolic Confinement

The binding energy of a shallow hydrogenic impurity of a spherical quantum dot confined by harmonic oscillator-like and by rectangular well-like potentials, using a variational procedure within the effective mass approximation, has been determined. The calculations of the binding energy of the donor impurity as a function of the system geometry, and the donor impurity position have been investigated. The binding energy of shallow donor impurity depends not only on the quantum confinements but also on the impurity position. Our results reveal that (i) the donor binding energy decreases as the dot size increases irrespective of the impurity position, and (ii) the binding energy values of rectangular confinement are larger than the values of parabolic confinement and (iii) the rectangular confinement is better than the parabolic confinement in a spherical quantum dot.

EFFECTS OF MAGNETIC AND ELECTRIC FIELDS ON THE HYDROGENIC IMPURITY IN AN ELLIPSOIDAL PARABOLIC QUANTUM DOT

2008 ◽  
Vol 15 (03) ◽  
pp. 201-205 ◽  
Author(s):  
E. KASAPOGLU ◽  
H. SARI ◽  
I. SOKMEN
Keyword(s):  
Binding Energy ◽  
Quantum Dot ◽  
Electric Fields ◽  
Magnetic Field Dependence ◽  
Hydrogenic Impurity ◽  
Mass Approximation ◽  
Donor Binding Energy ◽  
Potential Case ◽  
The Magnetic Field ◽  
Parabolic Quantum Dot

The binding energy of a hydrogen-like impurity in an ellipsoidal parabolic quantum dot under the magnetic and electric fields have been discussed by using the effective mass approximation and the variational method. We have calculated the effects of the magnetic and electric fields on the binding energy of donor impurities in the quantum dots with different confinement potentials. We conclude that the structural confinement is very effective, and especially in the weak confinement potential case the magnetic field dependence of the donor binding energy is more pronounced.

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.

EFFECT OF APPLIED ELECTRIC FIELD ON ACCEPTOR STATES IN ZINC-BLENDE InGaN/GaN QUANTUM DOT

2011 ◽  
Vol 25 (28) ◽  
pp. 2193-2201
Author(s):  
YINGNAI WEI ◽  
C. X. XIA ◽  
Y. M. LIU ◽  
Z. P. ZENG ◽  
S. Y. WEI
Keyword(s):  
Binding Energy ◽  
Quantum Dot ◽  
Electric Field ◽  
Applied Electric Field ◽  
Asymmetric Distribution ◽  
Left Boundary ◽  
Mass Approximation ◽  
Zinc Blende ◽  
Single Quantum Dot ◽  
Acceptor Binding Energy

Based on the effective-mass approximation, the acceptor binding energy in a cylindrical zinc-blende (ZB) InGaN / GaN single quantum dot (QD) is investigated variationally in the presence of the applied electric field. Numerical results show that the acceptor binding energy is highly dependent on the applied electric field, impurity positions and QD size. The applied electric field also induces an asymmetric distribution of the acceptor binding energy with respect to the center of the QD. Moreover, in the presence of the applied electric field, the acceptor binding energy is insensitive to dot height when the impurity is located at the left boundary of the ZB In 0.1 Ga 0.9 N / GaN QD with large dot height (H≥6 nm). In particular, the acceptor binding energy of the impurity located at the left boundary of the ZB In 0.1 Ga 0.9 N / GaN QD is identical for different dot height when the applied electric field F≥350 KV/cm. This result can be of interest for the technological purpose, as it could involve a source of control some impurity-related properties in these systems under the applied electric field.

First-excited-state energy of hydrogenic impurity bound polaron in an anisotropic quantum dot in an electric field

2019 ◽  
Vol 33 (32) ◽  
pp. 1950386
Author(s):  
Shi-Hua Chen
Keyword(s):  
Excited State ◽  
Binding Energy ◽  
Quantum Dot ◽  
Electric Field ◽  
Binding Energies ◽  
Hydrogenic Impurity ◽  
Bound Polaron ◽  
First Excited State ◽  
Trial Wavefunction ◽  
Anisotropic Quantum Dot

The first-excited-state (ES) binding energy of hydrogenic impurity bound polaron in an anisotropic quantum dot (QD) is obtained by constructing a variational wavefunction under the action of a uniform external electric field. As for a comparison, the ground-state (GS) binding energy of the system is also included. We apply numerical calculations to KBr QD with stronger electron–phonon (E–P) interaction in which the new variational wavefunction is adopted. We analyzed specifically the effects of electric field and the effects of both the position of the impurity and confinement lengths in the xy-plane and the [Formula: see text] direction on the ground and the first-ES binding energies (BEs). The results show that the selected trial wavefunction in the ES is appropriate and effective for the current research system.

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.

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