Strain Modification of Band Edge Energies in a Pyramidal InAs-GaAs Quantum Dot System

Abstract:

We present the calculated band edge energies altered by strain in a nanostructure system of a pyramidal InAs quantum dot buried in a GaAs substrate. Our zinc-blende supercell system of dimension 11.9 nm × 11.9 nm × 8.5 nm and 55119 atoms contains a pyramidal In770As886 quantum dot of 1656 atoms with height of 3.03 nm and square base of length 6.06 nm. The strain energy of this nanostructure system is minimized by employing the Keating formulation of interatomic potential and Monte Carlo relaxation method via the Metropolis algorithm. This relaxation is run for 20 million Monte Carlo steps at simulation temperature of 4.2 K. The calculated strain is then used to determine the conduction and valence band edge energies of the nanostructure. We find that along the [001] growth direction in the InAs quantum dot region, strain increases the conduction band edge energy by 0.6 eV and in the valence band strain results in relatively sharp wells at the dot base for heavy holes and at the dot tip for light holes. Thus, our calculation predicts that strain leads to increased band gap and spatial splitting of holes in this nanostructure system.

• Periodical: Advanced Materials Research (Volume 501)
• Pages: 337-341
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.501.337
• Online since: April 2012
• Authors: Gregory Henry Ripan, Geri Gopir, Ahmad Puaad Othman
• Keywords: Band Edge Energy, InAs/GaAs Quantum Dot, Keating Potential, Metropolis Monte Carlo, Nanostructure Valence Force Field, Strain Edge Energy

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