Electron beam pre-patterning for site-control of self-assembled InAs quantum dots on InP surfaces

A site control technique for individual InAs quantum dots (QDs) formed by s elf-assembling has been developed, using scanning electron microscope (SEM) assisted nano-deposition and metal organic vapor phase epitaxy (MOVPE). In a first step we characterize a device with randomly distributed InAs QDs o n InP, using resonant tunneling and transmission electron microscopy (TEM). Secondly, we use nano-scale deposits, created at the focal point, of the e lectron beam on an InP based heterostructure, as "nano growth masks". Growt h of a thin InP layer produces nano-holes above the deposits. The deposits are removed by oxygen plasma etching. When InAs is supplied on this surface , QDs are self-assembled at the hole sites, while no InAs dots are observed in the flat surface region. A vertical single electron tunneling device is proposed, using the developed technique.