InGaAs quantum disk: Fabrication via self-organization and spectroscopies

We have examined the spontaneous rearrangement of a strained InGaAs/AlGaAs heterostructure, on a (311)B, substrate into naturally ordered array of InG aAs disks automatically buried in Al-rich alloy. Unlike nano-islands formed via Stranski-Krastanov mechanism, it serves as a strong tendency to align themselves, We have stressed important interplay of islanding of the materi al with lattice mismatch, atomic diffusion across the interface between uns trained and strained materials, lateral mass transport, and development of the surface into low index surfaces with low surface energies: all these se ek to lower the total energy. Because of the damageless fabrication, these quantum disks showed excellent optical properties, which facilitated single -dot spectroscopy, Such spectroscopy revealed that lateral together with ve rtical confinement of exciton motion discretizes the exciton density-of-sta tes resulting in sharp and distinct photo emission/absorption spectra despi te their mesoscopic confinement. These characterize optical properties whic h are specific only to zero-dimensional system, thereby proving quantum dot characteristic. As for future device application, we undertook an attempt to artificially position the self-organized structure more accurately by pe riodic seeding an the virgin (311)B substrate. The results show that it is feasible to further improve the ordering of the array of quantum disks.