Quantitative Excited State Spectroscopy of a Single InGaAs Quantum Dot Molecule through Multi-million Atom Electronic Structure Calculations

Abstract

Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively reproduced, and the correct energy states are identified based on a previously validated atomistic tight binding model. The extended devices are represented explicitly in space with 15 million atom structures. An excited state spectroscopy technique is presented in which the externally applied electric field is swept to probe the ladder of the electronic energy levels (electron or hole) of one quantum dot through anti-crossings with the energy levels of the other quantum dot in a two quantum dot molecule. This technique can be applied to estimate the spatial electron-hole spacing inside the quantum dot molecule as well as to reverse engineer quantum dot geometry parameters such as the quantum dot separation. Crystal deformation induced piezoelectric effects have been discussed in the literature as minor perturbations lifting degeneracies of the electron excited (P and D) states, thus affecting polarization alignment of wave function lobes for III-V Heterostructures such as single InAs/GaAs quantum dots. In contrast this work demonstrates the crucial importance of piezoelectricity to resolve the symmetries and energies of the excited states through matching the experimentally measured spectrum in an InGaAs quantum dot molecule under the influence of an electric field. Both linear and quadratic piezoelectric effects are studied for the first time for a quantum dot molecule and demonstrated to be indeed important. The net piezoelectric contribution is found to be critical in determining the correct energy spectrum, which is in contrast to recent studies reporting vanishing net piezoelectric contributions.

Accepted for publication in IOP Nanotechnology Journal

References in corpus (12)

• Quantum Computation with Quantum Dots
• Electron transport through double quantum dots
• Direct Observation of Controlled Coupling in an Individual Quantum Dot Molecule
• Importance of second-order piezoelectric effects in zincblende semiconductors
• Optical Schemes for Quantum Computation in Quantum Dot Molecules
• High precision quantum control of single donor spins in silicon
• Theory of excitonic spectra and entanglement engineering in dot molecules
• Hole Spin Mixing in InAs Quantum Dot Molecules
• Moving towards nano-TCAD through multimillion atom quantum dot simulations matching experimental data
• Effect of anharmonicity of the strain energy on band offsets in semiconductor nanostructures
• Experimental and Theoretical Study of Polarization-dependent Optical Transitions from InAs Quantum Dots at Telecommunication-Wavelengths (1.3-1.5μm)
• Multimillion Atom Simulations with NEMO 3-D

Cited by in corpus (13)

• Tight-binding analysis of the electronic structure of dilute bismide alloys of GaP and GaAs
• Experimental and Atomistic Theoretical Study of Degree of Polarization from Multi-layer InAs/GaAs Quantum Dots
• Experimental and Theoretical Study of Polarization-dependent Optical Transitions from InAs Quantum Dots at Telecommunication-Wavelengths (1.3-1.5μm)
• Electron states in a double quantum dot with broken axial symmetry
• Coulomb mediated hybridization of excitons in artificial molecules
• Polarization Response in InAs Quantum Dots: Theoretical Correlation between Composition and Electronic Properties
• Donor hyperfine Stark shift and the role of central-cell corrections in tight-binding theory
• Limited accuracy of conduction band effective mass equations for semiconductor quantum dots
• Large-scale atomistic simulations demonstrate dominant alloy disorder effects in GaBi${}_x$As${}_{1-x}$/GaAs multiple quantum wells
• Understanding electric field control of electronic and optical properties of strongly-coupled multi-layer quantum dot molecules
• A variational quantum algorithm for tackling multi-dimensional Poisson equations with inhomogeneous boundary conditions
• Atomistic tight binding study of quantum confined Stark effect in GaBi${}_x$As${}_{1-x}$/GaAs quantum wells
• Nanowire design by deep learning for energy efficient photonic technologies