In this paper, we investigate the physics of electronic states in cubic InAs quantum dot periodic nanostructures embedded in GaAs. This study aims to provide an understanding of the physics of these systems so that they may be used in technological applications. We have focused on the effect of dot densities and dot sizes on the material properties, evaluating the miniband structure of electron states coming from the bulk conduction band, and have calculated the intraband photon absorption coefficient for several light polarizations. Strain is included in this analysis in order to obtain the conduction band offset between the materials by solving the Pikus-Bir 8×8 k·p Hamiltonian. We offer a comparison with approaches used by previous authors and clarify their range of validity. Finally, we draw our conclusions and propose future technological applications for these periodic arrangements.
The photon absorption coefficient in the arrays of InAs quantum dots embedded in GaAs is investigated. The influence of size and shape of the quantum dots on the miniband structure is analyzed. A detailed study is carried out in order to understand the physics relating to the absorption. The influence on the absorption coefficient due to the difference of energies between the lowest minibands, the joint density of states and the features of the wavefunctions are investigated in order to shed light on the phenomenon and understand it. The existence of thresholds in the absorption coefficient in the far infrared region, related to the shape of the quantum dots, is finally revealed, thus demonstrating that it may be an element to use both in future applications and in characterization of the materials.
We calculate the conduction miniband energy dispersion relation in an edge-defined silicon quantum wire periodic nanostructure embedded in SiO2. Our main aim is to predict the behavior of these nanostructures when used as components in optoelectronic devices such as, for example, photodetectors or intermediate-band solar cells. We take into consideration the effects of nonparabolicity and anisotropy and the different electron states arising from each valley when solving the Schrödinger equation. From these results, we investigate the intraband photon absorption coefficient for those transitions between minibands arising from the conduction band. We analyze the influence of light polarization and level of doping of the system in order to ascertain the best conditions for operation.
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