4 research outputs found
Charge Transport through Graphene Junctions with Wetting Metal Leads
Graphene is believed to be an excellent candidate material
for
next-generation electronic devices. However, one needs to take into
account the nontrivial effect of metal contacts in order to precisely
control the charge injection and extraction processes. We have performed
transport calculations for graphene junctions with wetting metal leads
(metal leads that bind covalently to graphene) using nonequilibrium
Green’s functions and density functional theory. Quantitative
information is provided on the increased resistance with respect to
ideal contacts and on the statistics of current fluctuations. We find
that charge transport through the studied two-terminal graphene junction
with Ti contacts is pseudo-diffusive up to surprisingly high energies
Intrinsic Defects, Fluctuations of the Local Shape, and the Photo-Oxidation of Black Phosphorus
Black phosphorus is a monatomic semiconducting
layered material
that degrades exothermically in the presence of light and ambient
contaminants. Its degradation dynamics remain largely unknown. Even
before degradation, local-probe studies indicate non-negligible local
curvatureî—¸through a nonconstant height distributionî—¸due
to the unavoidable presence of intrinsic defects. We establish that
these intrinsic defects are photo-oxidation sites because they lower
the chemisorption barrier of ideal black phosphorus (>10 eV and
out
of visible-range light excitations) right into the visible and ultraviolet
range (1.6 to 6.8 eV), thus enabling photoinduced oxidation and dissociation
of oxygen dimers. A full characterization of the material’s
shape and of its electronic properties at the early stages of the
oxidation process is presented as well. This study thus provides fundamental
insights into the degradation dynamics of this novel layered material
Intrinsic Defects, Fluctuations of the Local Shape, and the Photo-Oxidation of Black Phosphorus
Black phosphorus is a monatomic semiconducting
layered material
that degrades exothermically in the presence of light and ambient
contaminants. Its degradation dynamics remain largely unknown. Even
before degradation, local-probe studies indicate non-negligible local
curvatureî—¸through a nonconstant height distributionî—¸due
to the unavoidable presence of intrinsic defects. We establish that
these intrinsic defects are photo-oxidation sites because they lower
the chemisorption barrier of ideal black phosphorus (>10 eV and
out
of visible-range light excitations) right into the visible and ultraviolet
range (1.6 to 6.8 eV), thus enabling photoinduced oxidation and dissociation
of oxygen dimers. A full characterization of the material’s
shape and of its electronic properties at the early stages of the
oxidation process is presented as well. This study thus provides fundamental
insights into the degradation dynamics of this novel layered material
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SIGLECNRS RS 17660 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc