SELF-ORGANIZED MICROSTRUCTURE GROWTH

We present evidence of the new phenomenon of the direct growth of micr ostructures by metal-organic vapor-phase epitaxy (MOVPE) on high-index GaAs substrates. One- and zero-dimensional self-faceting by step bunc hing on GaAs (n11)A substrates produces quantum-wire- and dot-like arr ays on GaAs (311)A and GaAs (211)A substrates. The lateral periodicity of self-faceting is controlled by the layer thickness and growth temp erature and is directly correlated with the red shift of the luminesce nce of GaAs/AlGaAs heterostructures. On GaAs (n11)B substrates, well-o rdered quantum-dot arrays are formed in a new self-organizing growth m ode found in the MOVPE of a sequence of AlGaAs and strained InGaAs fil ms. The InGaAs film spontaneously interacts with AlGaAs buffer layers to form ordered arrays of disk-shaped InGaAs quantum dots buried withi n AlGaAs microcrystals due to lateral mass transport. The size and dis tance of the disks can be controlled independently by the In compositi on and the InGaAs layer thickness. Similar structures are also formed on InP (311)B substrates in the GaInAs/AIInAs and GaInAs/InP material systems. Lateral confinement of carriers in the disks is confirmed by the photoluminescence linewidth which, at room temperature, is as narr ow as 13 meV due to reduced thermal broadening.