Miniband structure and photon absorption in regimented quantum dot systems

Abstract

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.

Influence on miniband structure of size variations in regimented InAs/GaAs quantum dots arrays

“…This study has been carried out using the effective mass approach (EMA) in connection to previous works, where the influence of interdot distances, dot sizes, and shapes were investigated. 12,17 The influence of strain in conduction band offsets and effective masses were considered using the Pikus-Bir approach. 12 We have assumed uniform defect distributions within the samples, and calculated energy shifts using the first order perturbation theory.…”

“…12,17 The influence of strain in conduction band offsets and effective masses were considered using the Pikus-Bir approach. 12 We have assumed uniform defect distributions within the samples, and calculated energy shifts using the first order perturbation theory.…”

“…[7][8][9] From the theoretical point of view, several investigations have reported some physical features of such systems. Studies on thermal conduction, 10 charge transport, 11 and optical absorption 12,13 in these systems have been carried out in the last years.…”

“…The interest in the conduction band is justified primarily because it is more likely to have miniband gaps in this band, especially useful for optoelectronic applications, than in the valence band states due to the degeneracy of the bulk bands. In particular, this system has been explored in detail in previous works, 12,17 revealing the importance of quantum dot size or shape and interdot distances in the miniband formation. To extend these studies, and in order to approach the above physical phenomena due to breaks in the periodicity, we investigate how vacant quantum dots and wide quantum dots would influence in the miniband structures that we reported in previous researches.…”

Semiconductor Superlattice-Based Intermediate-Band Solar Cells

“…the distance between adjacent layers is large and the potential in the spacer material C forms a high barrier both for electrons and holes, the spectrum of the system is very close to that of a single isolated layer (Rodríguez-Bolívar et al, 2011). Figure 10(a) shows the electronic spectrum of the structure presented in Fig.…”