Few-electron semiconductor quantum dots with Gaussian confinement

Gómez, Sergio S.; Romero, Rodolfo H.

doi:10.2478/s11534-008-0132-z

Cited by 25 publications

(16 citation statements)

References 29 publications

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“…Therefore, the use of an open potential enables the study of different types of ionization processes. For the sake of the simplicity of the numerical calculations 26 and without loss of generality we use a Gaussian potential rather than a 3D open square well potential. The full potential of the system, V (r), is, therefore, where R is the distance between the QDs, and V L (V R ) and β L (β R ) are the potential depth and width of the left(right) QDs.…”

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confidence: 99%

Electron relaxation in quantum dots by the interatomic Coulombic decay mechanism

Cherkes

Moiseyev

2011

Phys. Rev. B

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Electron relaxation in quantum dot (QD) systems a has significant impact on QD optoelectronic devices such as lasers, photodetectors, and solar cells. Several different fundamental mechanisms are known. In this Brief Report we propose another possible relaxation mechanism which is based on the interatomic Coulombic decay (ICD) mechanism first predicted by Cederbaum and his coworkers in 1997 and has been recently observed in atomic van der Waals and in hydrogen-bonded molecular clusters. We show that the electron relaxation in a quantum dot dimer due to the ICD mechanism is on a picoseconds timescale. This mechanism enables us to design IR photodetectors which are extremely efficient for ultraweak radiation with a specific wavelength.Quantum dot (QD) based optoelectronic devices such as lasers, photodetectors, and solar cells are significantly affected by electron relaxation rates. Excited electrons can relax by various possible mechanisms. One such relaxation mechanism is photon emission, which is on the timescale of nanoseconds. 1 Another relaxation mechanism is due to strong interaction with longitudinal optical and acoustic phonons, 2-4 which is on the timescale of picoseconds. In addition a fast intradot Auger relaxation is possible on the timescale of few picoseconds and less. 5,6 In this Brief Report we propose another possible relaxation mechanism which, like the Auger mechanism, is an electron correlation effect. However, it is an interdot phenomenon and requires one electron excitation rather than two as in the intradot Auger relaxation. This new relaxation process is based on the interatomic Coulombic decay (ICD) mechanism first proposed by Cederbaum and his coworkers. 7 Since QDs are often referred to as artificial atoms, this electron relaxation mechanism should be applicable to QDs as well. We show in this Brief Report that electron relaxation in a quantum dot dimer, due to the ICD mechanism, is on a timescale of only a few picoseconds and occurs over a distance of 10 nm between the centers of the QDs.The ICD process is extremely efficient even in loosely bound atomic(molecular) clusters where the ionization of one atom(molecule) in the cluster results from the electronic relaxation of another, distant, atom(molecule). This process was first applied to hydrogen bonded molecular clusters, 7 and several years later also to neon dimers. 8,9 For the analysis of the ICD mechanism, see Refs. 10 and 11 and for a large variety of related processes see Refs. 12 and 13.Experimental observations have established ICD as an ultrafast and ubiquitous process. It was observed in atomic VDW clusters such as Ne n and ArNe 14-17 and in hydrogen bonded molecular clusters. 18,19 Ne clusters were experimentally shown to relax by ICD on the timescale of 33 fs for surface excited atoms and as fast as 6 fs for the bulk atoms. 17 The difference in the lifetime of bulk and surface atoms arises from an increase in the number of available ICD relaxation channels as the size of the cluster increases. 20 It is clear that ICD is mu...

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confidence: 99%

Electron relaxation in quantum dots by the interatomic Coulombic decay mechanism

Cherkes

Moiseyev

2011

Phys. Rev. B

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“…In Fig. 2, we show the behavior of average statistical energy of 3D QD with and without donor impurity as a [35] Numerov integration algorithm [35,36] Hypervirial-Pade method [37] Present work [ function of temperature (T). We observe that the average thermodynamic energy increases with increasing temperature (T).…”

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confidence: 99%

Heat capacity and entropy of Gaussian spherical quantum dot in the presence of donor impurity

2019

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The energy states of shallow donor impurity in GaAs/AlGaAs quantum dot heterostructure with Gaussian potential have been calculated by the shifted 1/N expansion method. The effects of the impurity on the ground state energy and average statistical energy have been investigated. The present calculations show that the donor impurity modifies significantly the electron energy levels of spherical quantum dot and thermal properties. In addition, we have also displayed the variations of the heat capacity and entropy of donor impurity in quantum dot with the radius, confining potential depth, dimension and temperature. The comparison shows that our results are in very good agreement with the theoretical reported work.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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“…The matrix elements of the spin operators are: 14). Now, we use the parabolic approximation [23], and consequently the levels of single particle energies are obtained as a function of z0 by the diagonalization of the potential V0+VL.S. The structure of levels is plotted in Fig.…”

Section: The Effect Of Spin-orbit Coupling On Levelsmentioning

confidence: 99%

Two-Center Gaussian Potential Well for Studying Light Nucleus in Cluster Structure

Roshanbakht

Shojaei

2017

Advances in High Energy Physics

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The clustering phenomena is very important to determine structure of light nuclei and deformation of spherical shape is inevitable. Hence, we calculated the energy levels of twocenter Gaussian potential well including spin-orbit coupling by solving the Schrödinger equation in the cylindrical coordinates. This model could predict the spin and parity of the light nucleus that have cluster structure consist of two identical clusters.

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Few-electron semiconductor quantum dots with Gaussian confinement

Cited by 25 publications

References 29 publications

Electron relaxation in quantum dots by the interatomic Coulombic decay mechanism

Electron relaxation in quantum dots by the interatomic Coulombic decay mechanism

Heat capacity and entropy of Gaussian spherical quantum dot in the presence of donor impurity

Two-Center Gaussian Potential Well for Studying Light Nucleus in Cluster Structure

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