Polarization Response in InAs Quantum Dots: Theoretical Correlation Between Composition and Electronic Properties

Muhammad Usman, Tyndall National Institute, Ireland
Vittorianna Tasco, National Nanotechnology Laboratory
Maria Teresa Todaro, National Nanotechnology Laboratory
Milena De Giorgi, National Nanotechnology Laboratory
Eoin P. O'Reilly, University College Cork
Gerhard Klimeck, Purdue University, Network for Computational Nanotechnology
Adriana Passaseo, National Nanotechnology Laboratory

Date of this Version



Nanotechnology, Volume 23, Number 16


III-V growth and surface conditions strongly influence the physical structure and resulting optical properties of self-assembled quantum dots (QDs). Beyond the design of a desired active optical wavelength, the polarization response of QDs is of particular interest for optical communications and quantum information science. Previous theoretical studies based on a pure InAs QD model failed to reproduce experimentally observed polarization properties. In this work, multi-million atom simulations are performed to understand the correlation between chemical composition and polarization properties of QDs. A systematic analysis of QD structural parameters leads us to propose a two layer composition model, mimicking In segregation and In-Ga intermixing effects. This model, consistent with mostly accepted compositional findings, allows to accurately fit the experimental PL spectra. The detailed study of QD morphology parameters presented here serves as a tool for using growth dynamics to engineer the strain field inside and around the QD structures, allowing tuning of the polarization response.


Nanoscience and Nanotechnology