NOVEL FORMATION METHOD OF QUANTUM-DOT STRUCTURES BY SELF-LIMITED SELECTIVE-AREA METALORGANIC VAPOR-PHASE EPITAXY

We have fabricated AlGaAs/GaAs quantum dot structures using selective area metalorganic vapor phase epitaxy (MOVPE). First, GaAs pyramidal structures with fourfold symmetric (011) facet sidewalls are formed on SiNx-masked (001) GaAs with square openings. Once the pyramidal structures were completely formed, no growth occurs on the top or sidewalls of the pyramids. Furthermore, the shape and width of the top area observed using 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 under different growth conditions. Sharp photoluminescence (PL) spectra are observed from uniform quantum dots.