Droplet Epitaxy for III-V Compound Semiconductor Quantum Nanostructures on Lattice Matched Systems

Abstract

During the Ga-molecules suppling on to the lattice-matched AlGaAs surface, we discussed the Ga-droplet formation dynamics based on Ga migration and diffusion behavior on GaAs (100), (111)A and (111)B surfaces. We discussed the formation mechanism of GaAs quantum dots (QDs), quantum dot molecules (QDMs; coupled QDs), single quantum rings (QRs), and double quantum rings (d-QRs; coupled QRs) complexes. Since the shape of GaAs quantum nanostructures (QNs) on (100) surface is affected by the out-migration of Ga-molecules due to the specific surface As coverage condition during crystallization, we can also control the shape of QNs by varying the conditions of droplet epitaxy process. In addition, by using the nature of the Ga-migration on the (111)A and (111)B surfaces, we fabricated ultra-high density (1.6 × 1011 /cm2) GaAs QDs and ultra-low density (6.5 × 105 /cm2) GaAs QNs on the AlGaAs (111)A and (111)B surfaces surface, respectively.