Abstract
We have investigated size- and excitation-intensity-dependent changes of the luminescence spectra of single As/GaAs quantum dots with diameters between 200 and 40 nm. The dot sizes investigated range from effectively two-dimensional structures down to diameters which are comparable to the length scales of electronic excitations, e.g., the excitonic Bohr radius, or of compositional fluctuations at interfaces. For dots occupied by single excitons, the luminescence linewidth decreases continuously with decreasing diameter. Using model calculations we relate this behavior to compositional fluctuations and obtain an estimate for their characteristic length scale. If the dots are occupied by several excitons the luminescence linewidth increases systematically with decreasing size. We describe this behavior by a model of carrier-carrier interaction effects on the luminescence linewidths. © 1996 The American Physical Society.
- Received 10 April 1996
DOI:https://doi.org/10.1103/PhysRevB.54.1510
©1996 American Physical Society