Self-limiting growth of quantum dot heterostructures on nonplanar {111}B substrates

We study the evolution of AlGaAs/GaAs growth during organometallic chemical vapor deposition on pyramidal recess patterns etched into GaAs $\text{{111}B}$ substrates. Cross-sectional atomic force microscopy clearly demonstrates the self-organized growth behavior in the inverted pyramid structures. During AlGaAs deposition, the side corners and the tip of the pyramid sharpen up to a self-limited radius of curvature of less than 10 nm. In addition, vertical Ga-rich AlGaAs quantum wells are formed at these corners. Subsequent GaAs growth results in the formation of GaAs quantum wires along the corners of the pyramid. These wires meet at the tip of the pyramid, forming a quantum dot structure at this point.