Vertical ordering and electronic coupling in bilayer nanoscale InAs/GaAs quantum dotsseparated by a thin spacer layer

Abstract

The vertical ordering and electronic coupling in bilayer nanoscale InAs/GaAsquantum dots separated by a thin (7–9 nm) spacer layer has been investigatedby transmission electron microscopy and photoluminescence measurements.The nanoscale dots are grown by molecular beam epitaxy (MBE) at0.028 ML s−1 growth rate. The active dots having higher monolayer coverages showed reduced orderingdue to local strain at the growth surface. Also the active dots with increased monolayercoverage is a probable cause of tunneling-assisted carrier transfer between the dotlayers.