The origin of the ballistic hole gas recently observed in Ge/Si core-shell nanowires has not been clearly resolved yet, although it is thought to be the result of the band offset at the radial interface. Here we perform spin-polarized density-functional calculations to investigate the defect levels of surface dangling bonds and Au impurities in the Si shell. Without any doping strategy, we find...

Boron doped graphene nanosheets (B-GR) as a p-type semiconductor, provides much more edges to facilitate the loading of TiO2 nanoparticles (P25). Highly-dispersed P25/B-GR nanosheets with the size of 20-50 nm, are successfully synthesized by the vacuum activation and ultraphonic method. The nanosized morphology can decrease the local density of defects which are induced by the boron substitutio...

We propose to replace Ga in (Ga,Mn)As with Li and Zn as a route to high Curie temperature, carrier mediated ferromagnetism in a dilute moment n-type semiconductor. Superior material characteristics, rendering Li(Zn,Mn)As a realistic candidate for such a system, include high solubility of the isovalent substitutional Mn impurity and carrier concentration controlled independently of Mn doping by ...

Carbon nanotubes, carbon nanocones, and graphene nanoribbons are carbon-based nanomaterials, and their electronic and field emission properties can be altered by either electron donors or electron acceptors. Among both donors and accepters, nitrogen and boron atoms are typical substitutional dopants for carbon materials. The contribution of this paper mainly provides a comprehensive overview of...

Methods for introducing new magnetic, optical, electronic, photophysical, or photochemical properties to semiconductor nanocrystals are attracting intense applications-oriented interest. In this communication, we report the preparation and electronic absorption spectroscopy of colloidal ZnO DMS-QDs. Our synthetic procedure involves modification of literature methods known to yield highly crysta...

Colloidal suspensions of charged polystyrene microspheres can self-organize into colloidal crystals, providing a three-dimensional periodic dielectric medium suitable for the study of photonic band structure effects in the infrared, near-infrared, and visible wavelength regimes. Light propagation along any particular direction in such a system displays bands of frequencies for which the propaga...

Tungsten doped titanium dioxide films with both transparent conducting oxide (TCO) and photocatalytic properties were produced via aerosol-assisted chemical vapor deposition of titanium ethoxide and dopant concentrations of tungsten ethoxide at 500 °C from a toluene solution. The films were anatase TiO2, with good n-type electrical conductivities as determined via Hall effect measurements. The ...

Based on first principles calculations, we investigate two probable types of deactivation mechanisms that hinder current efforts ofdoping ZnO p-type. (i) Passivation by Hydrogen. H prefers to bind with NO at the anti-bonding site and form NO–H complexes with abinding energy of about 1 eV. (ii) Passivation by the formation of substitutional diatomic molecules (SDM). Carbon impurities and...

The electronic structures of carbon nanotubes doped with oxygen dimers are studied using the ab initio pseudopotential density functional method. The fundamental energy gap of zigzag semiconducting nanotubes exhibits a strong dependence on both the concentration and configuration of oxygen-dimer defects that substitute for carbon atoms in the tubes and on the tube chiral index. For a certain ty...

The local structure of Mn-doped Li2B4O7(001) was investigated using extendedX-ray absorption fine structure (EXAFS) at the Mn K edge and electron paramagnetic resonance (EPR). The location of the Mn dopant in a lithium tetraborate crystal is consistent with occupation of a site with strong oxygen coordination. The Mn–O bond lengths are similar to those observed with Mn doping of the icosahedral...