2 research outputs found
Boosting DNA Recognition Sensitivity of Graphene Nanogaps through Nitrogen Edge Functionalization
One
of the challenges for next generation DNA sequencing is to
have a robust, stable, and reproducible nanodevice. In this work,
we propose how to improve the sensing of DNA nucleobase using functionalized
graphene nanogap as a solid state device. Two types of edge functionalization,
namely, either hydrogen or nitrogen, were considered. We showed that,
independent of species involved in the edge passivation, the highest-to-lowest
order of the nucleobase transmissions is not altered, but the intensity
is affected by several orders of magnitude. Our results show that
nitrogen edge tends to p-dope graphene, and most importantly, it contributes
with resonance states close to the Fermi level, which can be associated
with the increased conductance. Finally, the translocation process
of nucleobases passing through the nanogap was also investigated by
varying their position from a certain height (from +3 to −3
Ã…) with respect to the graphene sheet to show that nitrogen-terminated
sheets have enhanced sensitivity, as moving the nucleobase by approximately
1 Ã… reduces the conductance by up to 3 orders of magnitude
Highly Sensitive and Selective Gas Detection Based on Silicene
Recent advances in the fabrication
of silicene devices have raised
exciting prospects for practical applications such as gas sensing.
We investigated the gas detection performance of silicene nanosensors
for four different gases (NO, NO<sub>2</sub>, NH<sub>3</sub>, and
CO) in terms of sensitivity and selectivity, employing density functional
theory and nonequilibrium Green’s function method. The structural
configurations, adsorption sites, binding energies and charge transfer
of all studied gas molecules on silicene nanosensors are systematically
discussed in this work. Our results indicate that pristine silicene
exhibits strong sensitivity for NO and NO<sub>2</sub>, while it appears
incapable of sensing CO and NH<sub>3</sub>. In an attempt to overcome
sensitivity limitations due to weak van der Waals interaction of those
latter gas molecules on the device, we doped pristine silicene with
either B or N atoms, leading to enhanced binding energy as well as
charge transfer, and subsequently a significant improvement of sensitivity.
A distinction between the four studied gases based on the silicene
devices appears possible, and thus these promise to be next-generation
nanosensors for highly sensitive and selective gas detection