Optimizing the growth procedure for InAs quantum dot stacks by optical in situ techniques

Autor: T. Wehnert, F. Poser, E. Steimetz, Holm Kirmse, Wolfgang Richter, J.-T. Zettler, Wolfgang Neumann
Rok vydání: 2000
Předmět:
Zdroj: Journal of Crystal Growth. 221:592-598
ISSN: 0022-0248
DOI: 10.1016/s0022-0248(00)00784-3
Popis: The influence of the GaAs cap layer thickness on the surface morphology and stoichiometry of InAs quantum dot (QD) layers grown on GaAs(0 0 1) was investigated by real-time reflectance anisotropy spectroscopy (RAS) and ellipsometry. A redistribution of InAs from partially covered islands to the surface of the GaAs cap layer was found. Introducing a well-defined growth interruption (GRI) during cap layer growth, a narrower size distribution of the InAs islands could be achieved and, moreover, large clusters and dislocations in the sample could be completely avoided. Transmission electron microscopical images of stacked QD layers substantiate the growth model of island redistribution by showing a fractional second wetting layer. Using this procedure of island redistribution dislocation free 5-fold InAs QD stacks were realized.
Databáze: OpenAIRE