Hayne, M. and Young, R. J. and Smakman, E. P. and Nowozin, T. and Hodgson, Peter and Garleff, J. K. and Rambabu, P. and Koenraad, P. M. and Marent, A. and Bonato, L. and Schliwa, A. and Bimberg, D. (2013) The structural, electronic and optical properties of GaSb/GaAs nanostructures for charge-based memory. Journal of Physics D: Applied Physics, 46 (26): 264001. ISSN 0022-3727
Post_print_Hayne_J_Phys_D_Appl_Phys_2013_final.pdf - Accepted Version
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Abstract
The potential for GaSb nanostructures embedded in GaAs to operate as charge-based memory elements at room temperature is introduced and explored. Cross-sectional scanning-tunnelling microscopy is employed to directly probe and optimize the growth of nanostructures by molecular beam epitaxy. The results of structural analysis are combined with electrical measurements made with deep-level transient spectroscopy, showing excellent agreement with theoretical calculations which model the electronic structure of the nanostructures using 8-band k.p theory. Hole-localization energies exceeding 600 meV in quantum dots and near-100% material contrast between GaSb-rich quantum rings (QRs) and the surrounding GaAs matrix are revealed (no intermixing). Optical measurements confirm the depth of the hole localization, and demonstrate substantially lower inhomogeneous broadening than has previously been reported. Multiple peaks are partially resolved in ensemble photoluminescence of GaSb/GaAs QRs, and are attributed to charge states from discrete numbers of confined holes.