We report a new metallization process for achieving low resistance ohmic contacts to molecular beam epitaxy grown n-GaN (--Or7 cme3) using an Ah% bilayer metallization scheme. Four different thin-film contact metallizations were compared during the investigation, including Au, Al, Ti/Au, and Ti/Al layers. The metals were first deposited via conventional electron-beam evaporation onto the GaN su...

Claudia Rödl,1,2,3 Kari O. Ruotsalainen,4,5 Francesco Sottile,1,3 Ari-Pekka Honkanen,4 James M. Ablett,5 Jean-Pascal Rueff,5,6 Fausto Sirotti,5 Roberto Verbeni,7 Ali Al-Zein,7,8 Lucia Reining,1,3 and Simo Huotari4 1Laboratoire des Solides Irradiés, École polytechnique, CNRS, CEA, Université Paris-Saclay, 91128 Palaiseau cedex, France 2Institut für Festkörpertheorie und -optik, Friedrich-Schille...

Ladder-type polymers, obtained by small modifications of the atomic structure of ladder-type polythiophene, are studied using density-functional theory calculations. Within the local-density and GW approximations, it is found that upon a simple substitution of the sulfur atoms by nitrogen and boron atoms, the band structure of the resulting polymer exhibits band overlap between the occupied and...

We describe the lithographic control over the spectral response of three-dimensional photonic crystals. By precise microfabrication of the geometry using a reproducible and reliable procedure consisting of electron beam lithography followed by dry etching, we have shifted the conduction band of crystals within the near-infrared. Such microfabrication has enabled us to reproducibly define photon...

 The two-dimensional structure of graphene, consisting of an isotropic hexagonal lattice of carbon atoms, shows fascinating electronic properties, such as a gapless energy band and Dirac fermion behavior of electrons at fermi surface. Anisotropy can be induced in this structure by electrochemical pressure. In this article, by using tight-binding method, we review anisotropy effects in the elect...

This paper projects the enhanced drive current of a ntype electrostatically doped (ED) tunnel field-effect transistor (ED-TFET) based on heterojunction and band-gap engineering via TCAD 2-D device simulations. The homojunction ED-TFET device utilizes the electrostatic doping in order to create the source/drain region on an intrinsic silicon nanowire that also felicitates dynamic re-configurabil...

The optical band gap, extracted from absorption measurements, defines the figure of merit for transparent conducting oxides (TCOs). In many oxides, such as In O 2 3 or SnO2, inversion symmetry introduces a selection rule that blocks transitions from the valence-band maximum to the conduction-band minimum. This raises the absorption threshold and enlarges the optical gap relative to the fundamen...

nanoparticles of zirconium(iv) tungstate are prepared by chemical co-precipitation method. thecharacterizations have been carried out by tg/dta, dsc, afm, xrd, ftir and uv-vis spectrum. plspectrum shows two emission bands at 350 nm and at 477 nm. the effects of frequency on the dielectricbehavior and ac electrical conductivity have been studied. the dielectric constant is found to be 119.43 at1...