arXiv subjects

Pavel B. Sorokin

Publications and source records attributed to Pavel B. Sorokin.

22 records · Page 2Linked to original sources

arXiv2007

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.

cond-mat.mtrl-sci↗

arXiv2007

New symmetric families of silicon quantum dots and their conglomerates as a tunable source of photoluminescence in nanodevices

We propose a new variety of silicon quantum dots containing fullerene-derived hollows of nearly arbitrary symmetry. Conglomerate structures are designed by connecting the quantum dots through two kinds of junctions. The quantum confinement effect is investigated using semiempirical quantum-mechanical method. It is shown that within each family of quantum dots, the band gap and the stability are inversely proportional to the particle effective size. Quantum dots inherit a wide variety of structural and symmetry properties from their parent fullerenes. The conglomerates confine electrons like quasi-molecules with a peculiar electronic structure related to the junctions. Quantum dots and their conglomerates can host guest atoms in their hollows and therefore present a new promising type of tunable photoluminescent nanomaterials.

cond-mat.mtrl-sci↗

arXiv2007

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.

cond-mat.mtrl-sci↗

arXiv2007

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.

cond-mat.mtrl-sci↗