Abstract

The optical absorption spectrum of a nonuniform semiconductor quantum dot system is calculated. The effect of dot size deviation on the resolvability of the absorption peaks is estimated. The dots are assumed cubic with a size distribution described by a Gaussian function. The results show that the linewidth of each absorption peak is proportional to the ratio of the standard deviation of the dot size to the average dot size of the system ξ. As ξ increases, the line broadening causes overlap between nearby absorption peaks. The high-energy absorption peaks start overlapping first followed by the overlap of the low-energy absorption peaks. The calculated total absorption spectra, including both heavy hole transitions and light hole transitions, for GaAs quantum dot systems with ξ = 0.02, 0.05, and 0.10 are presented. It is shown that when ξ = 0.02 or less, the absorption peaks up to the fourth lowest level are separate; when ξ = 0.10 only the lowest heavy hole transition peak is resolvable.

© 1987 Optical Society of America