Pyramidal quantum dot structures by self-limited selective area metalorganic vapor phase epitaxy

Abstract

We have fabricated AlGaAs GaAs quantum dot structures using selective area metalorganic vapor phase epitaxy (MOVPE). First, GaAs pyramidal structures with four-fold symmetric [lcub]011[rcub] facet side walls are formed on SiN x masked (001) GaAs with square openings. After the pyramidal structures were completely formed, no growth occurs on the top or side walls of the pyramids. Furthermore, the shape and width of the top area observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM) is shown to be highly uniform. This indicates that self-limited growth occurs. Next, using these uniform pyramids, GaAs quantum dots are overgrown on top of the pyramids using different growth conditions. Sharp photoluminescence (PL) spectra are observed from uniform quantum dots.