Spatially site-controlled InAs quantum dot lattices

A spatial site-control method for InAs quantum dots (QDs) is proposed and demonstrated using ultrahigh vacuum in situ processing. Regular InAs QD arrays are initially prepared as strain templates on GaAs surfaces by the scanning tunneling microscope (STM) probe-assisted site-control technique. Multiple layers of InAs Stranski–Krastanov QDs are then grown with GaAs spacers for strain-induced vertical alignment above the regular QD arrays, resulting in three-dimensional QD lattices. Step-by-step STM observations reveal the growth mode of QDs in the vertical alignment process.