Structure of Si-capped Ge/SiC/Si (001) epitaxial nanodots: Implications for quantum dot patterning

Journal Article · Mon Apr 02 00:00:00 EDT 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3699223· OSTI ID:22025497

Petz, C W; Floro, J A ^[1]; Yang, D; Levy, J ^[2]

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1. Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)
2. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

Artificially ordered quantum dot (QD) arrays, where confined carriers can interact via direct exchange coupling, may create unique functionalities such as cluster qubits and spintronic bandgap systems. Development of such arrays for quantum computing requires fine control over QD size and spatial arrangement on the sub-35 nm length scale. We employ electron-beam irradiation to locally decompose ambient hydrocarbons onto a bare Si (001) surface. These carbonaceous patterns are annealed in ultra-high vacuum (UHV), forming ordered arrays of nanoscale SiC precipitates that have been suggested to template subsequent epitaxial Ge growth to form ordered QD arrays. We show that 3C-SiC nanodots form, in cube-on-cube epitaxial registry with the Si substrate. The SiC nanodots are fully relaxed by misfit dislocations and exhibit small lattice rotations with respect to the substrate. Ge overgrowth at elevated deposition temperatures, followed by Si capping, results in expulsion of the Ge from SiC template sites due to the large chemical and lattice mismatch between Ge and C. Maintaining an epitaxial, low-defectivity Si matrix around the quantum dots is important for creating reproducible electronic and spintronic coupling of states localized at the QDs.

• OSTI ID: 22025497
• Journal Information: Applied Physics Letters, Vol. 100, Issue 14; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
COUPLING
CRYSTAL LATTICES
DEPOSITION
DISLOCATIONS
ELECTRON BEAMS
ENERGY GAP
EPITAXY
FABRICATION
GERMANIUM
IRRADIATION
LAYERS
PHYSICAL RADIATION EFFECTS
PRECIPITATION
QUANTUM DOTS
SEMICONDUCTOR MATERIALS
SILICON
SILICON CARBIDES
SUBSTRATES