Quantum Confined Stark Shift and Ground State Optical Transition Rate in 100 Laterally Biased InAs/GaAs Quantum Dots

摘要

The atomistic tight binding simulator NEMO 3-D has previously been validated against the experimental data for quantum dots, wells, and wires in the InGaAlAs and SiGe material systems. Here, we demonstrate our new capability to compute optical matrix elements and transition strengths in tight binding. Systematic multi-million atom electronic structure calculations explore the quantum confined Stark shift and the ground state optical transition rate for an electric field in the lateral [100] direction. The simulations treat the strain in a ~15 million atom system and the electronic structure in a subset of ~9 million atoms. The effects of the long range strain, the optical polarization anisotropy, the interface roughness, and the non-degeneracy of the p-states which are missing in continuum methods like effective mass approximation or kldrp are included. A significant red shift in the emission spectra due to an applied in-plane electric field indicating a strong quantum confined Stark effect (QSCE) is observed. The ground state optical transition rate rapidly decreases with the increasing electric field magnitude due to reduced spatial overlap of ground electron and hole states.