Characterization of weak and strong dot-to-dot interaction in electronically coupled double quantum dots

This work presents the computation investigation of the dot-to-dot electronic coupling in quantum dots molecules by calculating and analyzing their photoelectron spectra.

Electronically coupled quantum dot molecules and quantum dot arrays are sources of unique electronic and optical properties because of controllable dot-to-dot interaction. Electron tunneling between the dots plays a crucial role in their application. In this work, we have calculated the photoelectron specta of PbS-PbS, PbS-CdS, and CdS-CdS to characterize the valence-band edge of these systems using electron-propagator approach.  The Dyson equation for these systems was constructed using 2nd-order approximation and the self-consistent solution of the Dyson equation were obtained to calculate the band-edge energies. The inter-dot separation distance for both strong and weak electronic coupling regimes, effect of dot size of the two contributing dots, the impact of semiconductor type, and the energy alignment of single-particle states between the dots were investigated. The results from these studies demonstrate that photoelectron spectra for these systems can be used to quantify dot-to-dot electronic coupling.