Site-controlled InAs quantum dots regrown on nonlithographically patterned GaAs

In this letter, a nonlithographic method for fabrication of high-quality site-controlled InAs quantum dots on GaAs is explored. The self-organized pores in nanochannel alumina (NCA) are used to define the nucleation sites of the site-controlled quantum dots. The pattern from the NCA is transferred to the GaAs substrate by electrochemical etching. The first layer of regrown InAs dots preferentially locate at the bottom of the etch pits on the GaAs substrate. Furthermore, cross-sectional transmission electron microscopy shows that when multiple layers of InAs dots are regrown, the dots will exhibit vertical alignment. To show the excellent optical quality of the regrown quantum dots, photoluminescence spectra are studied; room-temperature photo luminescence from the regrown dots is achieved