701 research outputs found
Multiterminal Nanowire Junctions of Silicon: A Theoretical Prediction of Atomic Structure and Electronic Properties
Using empirical scheme, atomic structure of a new exotic class of silicon
nanoclusters was elaborated upon the central icosahedral core (Si-IC) and
pentagonal petals (Si-PP) growing from Si-IC vertexes. It was shown that
Si-IC/Si-PP interface formation is energetically preferable. Some experimental
observations of silicon nanostructures can be explained by presence of the
proposed objects. The Extended Huckel Theory electronic structure calculations
demonstrate an ability of the proposed objects to act as nanoscale tunnel
junctions.Comment: 13 pages, 3 figures, 1 tabl
The theoretical DFT study of electronic structure of thin Si/SiO2 quantum nanodots and nanowires
The atomic and electronic structure of a set of proposed thin (1.6 nm in
diameter) silicon/silica quantum nanodots and nanowires with narrow interface,
as well as parent metastable silicon structures (1.2 nm in diameter), was
studied in cluster and PBC approaches using B3LYP/6-31G* and PW PP LDA
approximations. The total density of states (TDOS) of the smallest
quasispherical silicon quantum dot (Si85) corresponds well to the TDOS of the
bulk silicon. The elongated silicon nanodots and 1D nanowires demonstrate the
metallic nature of the electronic structure. The surface oxidized layer opens
the bandgap in the TDOS of the Si/SiO2 species. The top of the valence band and
the bottom of conductivity band of the particles are formed by the silicon core
derived states. The energy width of the bandgap is determined by the length of
the Si/SiO2 clusters and demonstrates inverse dependence upon the size of the
nanostructures. The theoretical data describes the size confinement effect in
photoluminescence spectra of the silica embedded nanocrystalline silicon with
high accuracy.Comment: 22 pages, 5 figures, 1 tabl
Two-dimensional semiconducting nanostructures based on single graphene sheets with lines of adsorbed hydrogen atoms
It is shown that lines of adsorbed hydrogen pair atoms divide the graphene
sheet into strips and form hydrogen-based superlattice structures (2HG-SL). We
show that the forming of 2HG-SL drastically changes the electronic properties
of graphene from semimetal to semiconductor. The electronic spectra of "zigzag"
(n,0) 2HG-SL is similar to that of (n,0) carbon nanotubes and have a similar
oscillation of band gap with number n, but with non-zero minimal values. The
composite dual-periodic (n,0)+(m,0) 2HG-SLs of "zigzag" strips are analyzed,
with the conclusion that they may be treated as quasi-two-dimensional
heterostructures. We also suggest an experimental way of fabricating hydrogen
superlattices.Comment: 12 pages, 3 figure
Influence of Native Defects on the Electronic and Magnetic Properties of CVD Grown MoSe<sub>2</sub> Single Layers
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