Homogeneous linewidth of optical transitions and multiple electron-LO-phonon scattering in quantum dots

The main electronic spectral density peaks of the optical lines in semicond uctor quantum dots an shown to depend on the energy variable as 1/root(E). It is shown that the experimental data of the measurements of the lineshape and the linewidth should be expected to be limited considerably by the spe ctral resolution of the experimental apparatus. The optical lineshape of th e optical lines active in the luminescent transitions are calculated numeri cally together with the dependence of the linewidth on temperature and the size of the quantum dot. The electronic relaxation time, dependent on the o verlap of two electronic spectral densities, is shown to be in the range of about 100 fs to 1 ps. The theory is based on the electron multiple scatter ing on optical phonons and on multiphonon states of the electron-LO-phonon system of quantum dots. The electronic self-energy is calculated in the sel f-consistent Born approximation. (C) 2000 Elsevier Science B.V. All rights reserved.