Publication

Band gaps and dielectric constants of amorphous hafnium silicates: A first-principles investigation

Publications associées (39)

Charge transition levels of carbon-, oxygen-, and hydrogen-related defects at the SiC/SiO2 interface through hybrid functionals

Alfredo Pasquarello, Peter Broqvist, Audrius Alkauskas, Fabien Devynck

We calculate charge transition levels of various defects at the SiC/SiO2 interface within a scheme based on hybrid density functionals, which accurately reproduce the involved band gaps and band offsets. The defect levels are first evaluated in bulk models ...

2011

Transient phenomenological modeling of photoelectrochemical cells for water splitting - Application to undoped hematite electrodes

A phenomenological model is proposed for a better understanding of the basic mechanisms of photoelectrochemical (PEC) cells. The main assumptions of the one-dimensional transient phenomenological model are: i) bulk recombination of the conduction band elec ...

Elsevier2011

Untangling the Electronic Band Structure of Wurtzite GaAs Nanowires by Resonant Raman Spectroscopy

Anna Fontcuberta i Morral, Martin Heiss, Emanuele Uccelli, Bernt Ketterer

In semiconductor nanowires, the coexistence of wurtzite and zinc-blende phases enables the engineering of the electronic structure within a single material. This presupposes an exact knowledge of the band structure in the wurtzite phase. We demonstrate tha ...

American Chemical Society2011

Charge transition levels of nitrogen dangling bonds at Si/SiO2 interfaces: A first-principles study

Alfredo Pasquarello, Peter Broqvist, Philipp Dahinden

The defect levels of the nitrogen dangling bond at the Si/SiO2 interface are determined through a density-functional approach. The composition grading at the interface is modeled through crystalline and amorphous models of stoichiometric SiO2, nitrided SiO ...

2010

Dopamine Adsorption on Anatase TiO2(101): A Photoemission and NEXAFS Spectroscopy Study

The adsorption of dopamine onto an anatase TiO2(101) single crystal has been studied using photoemission and NEXAFS techniques Photoemission Jesuits suggest that the dopamine molecule adsorbs on the surface in a bidentate geometry, resulting in the removal ...

American Chemical Society2010

Charge migration in Pb(Zr,Ti)O3 ceramics and its relation to ageing, hardening and softening

Dragan Damjanovic

The dielectric response of hard (Fe-doped) and soft (Nb-doped) rhombohedral Pb(Zr0.58Ti0.42)1−xMexO3 (Me=Fe or Nb) ceramics was studied at subswitching conditions over a wide range of temperatures (50– 450 °C) and frequencies (10 mHz to 10 kHz). The result ...

2010

Photocatalytic Redox Reactions for In-Source Peptide Fragmentation

Hubert Girault, Jérôme Waser, Liang Qiao, Hongyan Bi

In-source photocatalytic redox reactions based on a photosensitive target plate have been developed to realize peptide fragmentation during laser desorption ionization. Sample peptides and glucose are simply deposited on a spot of sintered TiO2 nanoparticl ...

2009

Electronic Structure and Transport Properties of Ternary Skutterudite: CoX(3/2)Y(3/2)

Nicola Marzari, Boris Kozinsky

Electronic properties of ternary skutterudites AX(3/2)Y(3/2) (A=Co, X=Ge, Sn and Y=S, Te) are investigated using first principles calculations to clarify recent experimental results. Band derivatives are computed accurately within an approach based on Maxi ...

Materials Research Society2009

Amorphous hafnium silicates: structural, electronic and dielectric properties

Alfredo Pasquarello, Peter Broqvist

Models of amorphous (HfO2)x(SiO2)(1), for varying hafnium, content x are generated by ab initio molecular dynamics. The structural properties are analyzed in terms of pair distribution functions from which typical bond lengths and coordination numbers are ...

2007

Hydrogen in Si(100)-SiO2-HfO2 gate stacks: Relevant charge states and their location

Alfredo Pasquarello, Peter Broqvist

Using a density functional approach, we study the energetics of various charged hydrogen states in the Si(100)-SiO2-HfO2 gate stack. We describe the SiO2-HfO2 transition region through model structures of amorphous hafnium silicate HfxSi1-xO2 with differen ...

2007

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