Spatial point analysis of quantum dot nucleation sites on InAs wetting layer

We perform spatial point analysis of InAs quantum dot (QD) nucleation sites and surface reconstruction domain patterns on an InAs wetting layer to investigate QD nucleation mechanisms in Stranski-Krastanow growth mode. An InAs wetting layer on a GaAs(001) substrate has been observed at 300 degrees C by using in situ scanning tunneling microscopy (STM) preceding QD formation. A nearest-neighbor analysis of the STM images finds that the point pattern of QD precursors is similar to that of (1 x 3)/(2 x 3) surface reconstruction domains which are specific to Ga-rich fluctuation. This provides the evidence that InAs QD nucleation is induced by Ga-rich fluctuation within an InAs wetting layer, as a technical implication for site-controlled QD growth for various QD devices. (C) 2011 Elsevier B.V. All rights reserved.