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Pulgar-Velásquez L, Sierra-Ortega J, Vinasco JA, Laroze D, Radu A, Kasapoglu E, Restrepo RL, Gil-Corrales JA, Morales AL, Duque CA. Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2832. [PMID: 34835595 PMCID: PMC8619694 DOI: 10.3390/nano11112832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/27/2022]
Abstract
Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe-CdTe core-shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system's azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe-CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry.
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Affiliation(s)
- Lorenz Pulgar-Velásquez
- Grupo de Investigación en Teoría de la Materia Condensada, Universidad del Magdalena, Santa Marta 470004, Colombia; (L.P.-V.); (J.S.-O.)
| | - José Sierra-Ortega
- Grupo de Investigación en Teoría de la Materia Condensada, Universidad del Magdalena, Santa Marta 470004, Colombia; (L.P.-V.); (J.S.-O.)
| | - Juan A. Vinasco
- Instituto de Alta Investigación, CEDENNA, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (J.A.V.); (D.L.)
| | - David Laroze
- Instituto de Alta Investigación, CEDENNA, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile; (J.A.V.); (D.L.)
| | - Adrian Radu
- Department of Physics, “Politehnica” University of Bucharest, 313 Splaiul Independenţei, RO 060042 Bucharest, Romania;
| | - Esin Kasapoglu
- Department of Physics, Faculty of Science, Sivas Cumhuriyet University, Sivas 58140, Turkey;
| | - Ricardo L. Restrepo
- EIA-Física Teórica y Aplicada, Universidad EIA, Envigado PC 055428, Colombia;
| | - John A. Gil-Corrales
- Grupo de Materia Condensada-UdeA, Facultad de Ciencias Exactas y Naturales, Instituto de Física, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín AA 1226, Colombia; (J.A.G.-C.); (A.L.M.)
| | - Alvaro L. Morales
- Grupo de Materia Condensada-UdeA, Facultad de Ciencias Exactas y Naturales, Instituto de Física, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín AA 1226, Colombia; (J.A.G.-C.); (A.L.M.)
| | - Carlos A. Duque
- Grupo de Materia Condensada-UdeA, Facultad de Ciencias Exactas y Naturales, Instituto de Física, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín AA 1226, Colombia; (J.A.G.-C.); (A.L.M.)
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Miah MI. Photo-Induced Spin Dynamics in Semiconductor Quantum Wells. NANOSCALE RESEARCH LETTERS 2009; 4:385-388. [PMID: 20596548 PMCID: PMC2893598 DOI: 10.1007/s11671-008-9241-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 12/30/2008] [Indexed: 05/29/2023]
Abstract
We experimentally investigate the dynamics of spins in GaAs quantum wells under applied electric bias by photoluminescence (PL) measurements excited with circularly polarized light. The bias-dependent circular polarization of PL (P(PL)) with and without magnetic field is studied. The P(PL) without magnetic field is found to be decayed with an enhancement of increasing the strength of the negative bias. However, P(PL) in a transverse magnetic field shows oscillations under an electric bias, indicating that the precession of electron spin occurs in quantum wells. The results are discussed based on the electron-hole exchange interaction in the electric field.
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Affiliation(s)
- M Idrish Miah
- Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD, 4111, Australia
- School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD, 4111, Australia
- Department of Physics, University of Chittagong, Chittagong, 4331, Bangladesh
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