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HL: Fachverband Halbleiterphysik
HL 64: Poster II
HL 64.16: Poster
Donnerstag, 19. März 2020, 10:00–13:00, P1A
Self-assembled low-density InAs quantum dots/quantum dot molecules — •Akshay Kumar Verma, Timo Langer, and Dirk Reuter — Paderborn University, Department Physik, Warburger Str. 100, 33098 Paderborn
In recent years, low-density InAs Quantum dots (QDs)/Quantum dot molecules (QDMs) have been fabricated and studied by single dot spectroscopy for their unique optical and electrical properties. For single dot based experiments, the density requirement is around 108 QDs/cm2 (∼1QD/µm2) or below for which a dot does not interact with neighbouring dots and can optically be addressed individually. Self-assembled InAs quantum dot layer(s) were grown on GaAs (100) substrates by molecular beam epitaxy (MBE) using two growth approaches, In-gradient approach, and annealing approach, resulting in densities from 108-1010 QDs/cm2. The size, shape, and density of QDs were controlled by a variation of the growth parameters. In the annealing approach, we deposit a subcritical InAs amount with continuous substrate rotation, with subsequent annealing. The transition energies can be tuned by using the In-flush technique. We have grown two vertically InAs QDs layers separated by GaAs barrier, so called QDMs. The QDs have been analyzed by atomic force microscopy and photoluminescence (PL). By carefully adjusting the substrate temperature and In amount, we were able to obtain QD densities of ∼107-108 QDs/cm2 homogenously over an entire 3" wafer. We suggest that the low-density InAs QDs/QDMs grown by annealing approach provide us a large fraction of the wafer for further experiments.