Substrate Index Dependence of Energy Levels in In_(0.4) Ga_(0.6) As/GaAs Quantum Dots Applicable to QD-Lasers (a six-band k.p approximation)

TL;DR

This study investigates how substrate index influences energy levels and strain in InGaAs/GaAs quantum dots using a six-band k.p model, revealing significant effects on band gap and transition energies relevant for quantum dot laser design.

Contribution

It provides a detailed analysis of substrate index dependence on energy levels and strain in quantum dots using a six-band k.p approximation, highlighting the impact on optical properties.

Findings

Substrate index significantly affects band gap and transition energies.

Strain tensor components are highly sensitive to substrate surface index.

Results align well with existing formulas and research.

Abstract

Quantum dot lasers have been the focus of researchers due to their interesting optical properties owing to quantum confinement of carriers. In epitaxial quantum dots formed on a substrate, band-edge diagrams sound to more complex than simple bulk materials because of the important role of strain. Strain tensor is strongly dependent to lattice mismatch. Various substrate indexes have been used in the laser devices, and a number of research groups elaborate to find the best substrate index. In this research band edge, energy levels and strain effects of cubic In_0.4 Ga_0.6 As-GaAs quantum dots are studied by 6-band k.p model and their dependence to substrate index is investigated. It is shown that change of substrate index affects the band gap and transition energy of electrons and holes. Moreover, we show that components of strain tensor are strongly sensitive to surface index, and symmetry breaks along space. Our results appear to be in very good consonance with represented formula and similar researches. Keywords: substrate index, quantum dot laser, band edge, strain tensor.