STABILITY OF AN EXCITON BOUND TO AN IONIZED ACCEPTOR IN QUANTUM DOTS

2003 ◽  
Vol 17 (11) ◽  
pp. 2273-2279 ◽  
Author(s):  
S. BASKOUTAS ◽  
A. F. TERZIS ◽  
C. POLITIS
Keyword(s):  
Quantum Dots ◽  
Binding Energy ◽  
Quantum Dot ◽  
Numerical Method ◽  
Schrodinger Equation ◽  
Critical Radius ◽  
Critical Value ◽  
Two Dimensional ◽  
Mass Ratio ◽  
Acceptor Impurity

Binding energy for an exciton (X) bound in a parabolic two-dimensional quantum dot by an acceptor impurity A- located on the z-axis at a distance d from the dot plane, are calculated using the Hartree formalism with a recently developed numerical method (PMM) for the solution of the Schrödinger equation. As our analysis indicates there is a critical dot radius Rc such that for R < Rc the complex (A-, X) is unstable and with an increase of the impurity distance this critical radius increases. Furthermore, there is a critical value σc of the mass ratio [Formula: see text] such that for σ > σc the complex is stable.

Ge Quantum Dot Memory Structure with Laterally Ordered Highly Dense Arrays of Ge Dots

2007 ◽  
Vol 7 (1) ◽  
pp. 316-321 ◽  
Author(s):  
A. G. Nassiopoulou ◽  
A. Olzierski ◽  
E. Tsoi ◽  
I. Berbezier ◽  
A. Karmous
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Silicon Substrate ◽  
Ion Beam ◽  
Memory Structure ◽  
Two Dimensional ◽  
Electrical Measurements ◽  
Chemical Cleaning ◽  
Ge Quantum Dot ◽  
Field Oxide

This work was devoted to the development of a Ge quantum dot memory structure of a MOSFET type with laterally ordered Ge quantum dots within the gate dielectric stack. Lateral ordering of the Ge dots was achieved by the combination of the following technological steps: (a) use of a focused ion beam (FIB) to create ordered two-dimensional arrays of regular holes on a field oxide on the silicon substrate, (b) chemical cleaning and restoring of the Si surface in the holes, (c) further oxidation to transfer the pattern from the field oxide to the silicon substrate, (d) removal of the field oxide and thermal re-oxidation of the sample in order to create a tunneling oxide of homogeneous thickness on the patterned silicon surface, and (e) self-assembly of the two-dimensional arrays of Ge dots on the patterned tunneling oxide. The charging properties of the obtained memory structure were characterized by electrical measurements. Charging of the Ge quantum dot layer by electrons injected from the substrate resulted in a large shift in the capacitance-voltage curves of the MOS structure. Charges were stored in deep traps in the charging layer, and consequently the erasing process was difficult, resulting in a limited memory window. The advantages of controlled positioning of the quantum dots in the charging layer will be discussed.

Exact Numerical Procedure for the Binding Energy of Hydrogen Impurities in Quantum Dots with Parabolic Confinements

2013 ◽  
Vol 475-476 ◽  
pp. 1355-1358
Author(s):  
Arnold Abramov
Keyword(s):  
Quantum Dots ◽  
Wave Function ◽  
Binding Energy ◽  
Quantum Dot ◽  
Excited States ◽  
Ground State ◽  
Qualitative Agreement ◽  
Numerical Procedure ◽  
Impurity States ◽  
Parabolic Confinement

In this paper we present exact numerical procedure to calculate the binding energy and wave function of impurity states in a quantum dot with parabolic confinement. The developed method allows control the accuracy of obtained results, as well as calculates the characteristics of not only ground state, but also of the excited states. Comparison of our results with data obtained by other methods is in quantitative and qualitative agreement. We studied the effects of impurity position on the binding energy.

SUBSTRATE MODULATED GRAPHENE QUANTUM DOTS

2012 ◽  
Vol 26 (25) ◽  
pp. 1250162
Author(s):  
QIONG MA ◽  
TAO TU ◽  
LI WANG ◽  
HAI-OU LI ◽  
ZHI-RONG LIN ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Energy Spectrum ◽  
Quantum Dot ◽  
Transport Properties ◽  
Coupling Strength ◽  
Graphene Quantum Dots ◽  
Two Dimensional ◽  
Promising Candidate ◽  
Gapped Graphene ◽  
Practical Applications

We propose a method to use gapped graphene as barriers to confine electrons in gapless graphene and form a good quantum dot, which can be realized on an oxygen-terminated SiO 2 substrate partly hydrogen-passivated. In particular, we use deposited ferromagnetic insulators as contacts which give rise to spin-dependent energy spectrum and transport properties. Furthermore, we upgrade this method to form two-dimensional quantum dot arrays, whose coupling strength between neighboring dots can be uniquely anisotropic. Compared to complexity of other approaches to form quantum dot in graphene, the setup suggested here is a promising candidate for practical applications.

scholarly journals Interdot carrier and spin dynamics in a two-dimensional high-density quantum-dot array of InGaAs with quantum dots embedded as local potential minima

2019 ◽  
Vol 34 (2) ◽  
pp. 025001 ◽  
Author(s):  
Satoshi Hiura ◽  
Masayuki Urabe ◽  
Kazuki Takeishi ◽  
Kodai Itabashi ◽  
Junichi Takayama ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Spin Dynamics ◽  
High Density ◽  
Local Potential ◽  
Two Dimensional

Osscillating Binding Energy of a Donor Impurity Confined Within CdS-SiO2 Constant Total Effective Radius Multi-Shells Quantum Dots

2016 ◽  
Vol 15 (01n02) ◽  
pp. 1650003
Author(s):  
M. Solaimani
Keyword(s):  
Quantum Dots ◽  
Binding Energy ◽  
Quantum Dot ◽  
Outer Radius ◽  
Effective Radius ◽  
Wave Functions ◽  
Donor Impurity ◽  
Single Donor ◽  
Number Variation

In this paper, we have studied the effect of a number of wells and quantum dot thickness on binding energy of a single donor impurity confined within a CdS-SiO2 constant total effective radius multi-shells quantum dot (CTER-MSQD) system. We have shown that impurity binding energy versus number of wells in a quantum dot with fixed outer radius oscillates when amplitude increases. By using well number variation, adding impurity and changing quantum dot radius as three tuning tools, localization of wave-functions in each part of the quantum dot along the radius has been now made possible. Finally, adding the impurity leads to more probability of finding the electrons in the wells near the center of the quantum dot.

scholarly journals A numerical study of the Bénard cell

1971 ◽  
Vol 45 (4) ◽  
pp. 805-829 ◽  
Author(s):  
André Cabelli ◽  
G. de Vahl Davis
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Numerical Method ◽  
Liquid Surface ◽  
Numerical Study ◽  
Three Dimensional ◽  
Critical Value ◽  
Two Dimensional ◽  
Surface Tension Forces ◽  
Biot Numbers

When a layer of liquid is heated from below at a rate which exceeds a certain critical value, a two- or three-dimensional motion is generated. This motion arises from the action of buoyancy and surface tension forces, the latter being due to variations in the temperature of the liquid surface.The two-dimensional form of the flow has been studied by a numerical method. It consists of a series of rolls, rotating alternately clockwise and anticlockwise, which are shown to be symmetrical about the dividing streamlines. As well as a detailed description of the motion and temperature of the liquid, and of the effects on these characteristics of variations in the Rayleigh, Marangoni, Prandtl and Biot numbers, a study has been made of the conditions under which the motion first starts, the wavelength of the rolls and the rate of heat transfer across the liquid layer.

Sign in / Sign up

Export Citation Format

Share Document