An Analytical Approach to study Annealing Induced Interdiffusion of In and Ga for Truncated Pyramidal InAs/GaAs Quantum Dots

A strain-assisted model for studying the annealing induced interdiffusion of constituent atoms in truncated pyramidal InAs/GaAs self-assembled quantum dot (QD) is developed. In our model, we have considered the equiprobable diffusion of Ga and In atoms in and out of the QD system, thereby resulting in the formation of In rich In1-xGaxAs as the QD material and a combination of Ga rich InxGa1-xAs and GaAs barrier material. This assumption is supported by the high-resolution cross-sectional transmission electron microscopy (HRTEM) images and high-resolution X-ray diffraction (HRXRD) plots of the as-grown and annealed samples. First principle calculations are utilized to evaluate the strain and annealing temperature dependent activation energy, which further assists to solve the Fickian diffusion model. Our simplistic model provides a detailed insight into the effect of annealing phenomenon on the bimodal Photoluminescence (PL) spectra of molecular beam epitaxy (MBE) grown InAs/GaAs QDs, which have evolved as a potential system for innumerous applications including single photon sources, quantum computers, spin LEDs, LASERs and Infrared Photodetectors.