Interplay between thermodynamics and kinetics in the capping of InAs/GaAs (001) quantum dots Journal Article


Author(s): Costantini, Giovanni; Rastelli, Armando; Manzano, Carlos; Acosta-Diaz, P; Songmuang, Rudeeson; Katsaros, Georgios; Schmidt, Oliver G; Kern, Klaus
Article Title: Interplay between thermodynamics and kinetics in the capping of InAs/GaAs (001) quantum dots
Affiliation
Abstract: A microscopic picture for the GaAs overgrowth of self-organized InAs/GaAs(001) quantum dots is developed. Scanning tunneling microscopy measurements reveal two capping regimes: the first being characterized by a dot shrinking and a backward pyramid-to-dome shape transition. This regime is governed by fast dynamics resulting in island morphologies close to thermodynamic equilibrium. The second regime is marked by a true overgrowth and is controlled by kinetically limited surface diffusion processes. A simple model is developed to describe the observed structural changes which are rationalized in terms of energetic minimization driven by lattice mismatch and alloying.
Keywords: Thermodynamics; Diffusion; Microscopic examination; Semiconductor quantum dots; Kinetic theory; Semiconducting gallium; Semiconductor growth; Shrinkage; Dot shrinking; Energetic minimization; Island morphologies; Lattice mismatch; Thermodynamic equilibrium
Journal Title: Physical Review Letters
Volume: 96
Issue 22
ISSN: 1079-7114
Publisher: American Physical Society  
Date Published: 2006-01-01
Start Page: Article number 226106
DOI: 10.1103/PhysRevLett.96.226106
Open access: no