Electron–hole transition in a spherical quantum dot confined at the center of a cylindrical nano-wire: Comparison of isotropic and anisotropic effective mass

• Published in: Superlattices and microstructures 2012-10, Vol.52 (4), p.669-677
• Main Authors: Safarpour, Gh, Barati, M., Moradi, M.
• Format: Article
• Language: English
• Subjects: Anisotropic and isotropic effective mass; Anisotropy; Gallium arsenide; Mathematical analysis; Nano-wire; Nanocomposites; Nanomaterials; Nanostructure; Quantum dots; Spherical quantum dot; Wavelengths
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2012.06.017

In this paper the energy levels and emitted wavelengths have been calculated for a spherical QD which placed at the center of a cylindrical nano-wire. [Display omitted] ► A spherical quantum dot is considered at the center of a cylindrical nano-wire. ► The finite element method has been used to solve Schrodinger equation. ► Two types of heavy holes with isotropic and anisotropic effective mass are considered. ► We found that energy levels decrease as the dot radius or nano-wire radius increases. ► We also found that emitted wavelengths increase as the dot or nano-wire radius increases. Electronic structure of an InAs spherical quantum dot placed at the center of a GaAs cylindrical nano-wire is investigated. The Schrodinger equation within the effective mass approximation is solved and the energy eigenvalues and transition energies are calculated as a function of quantum dot and nano-wire radii using the finite element method. The two types of heavy holes, hhI and hhII, with isotropic and anisotropic effective masses are considered, respectively. The effect of spherical and nano-wire confining potentials, the size of the dot and the nano-wire on ground and first excited state energies of the electron, heavy hole I and heavy hole II are investigated. The results show that the electron and heavy holes energies decrease as the dot and the nano-wire radii increase. The emitted wavelength of transitions between el-hhI and el-hhII are also calculated and compared. The results show that the anisotropy of the effective mass has great effect on the emitted wavelength.