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 s tructures with fourfold symmetric (011) facet sidewalls are formed on SiNx-masked (001) GaAs with square openings. Once the pyramidal struct ures were completely formed, no growth occurs on the top or sidewalls of the pyramids. Furthermore, the shape and width of the top area obse rved using a scanning electron microscope (SEM) and an atomic force mi croscope (AFM) is shown to be highly uniform. This indicates that self -limited growth occurs. Next, using these uniform pyramids, GaAs quant um dots are overgrown on top of the pyramids under different growth co nditions. Sharp photoluminescence (PL) spectra are observed from unifo rm quantum dots.