65 research outputs found
Real-Time Detection of Deoxyribonucleic Acid Bases via their Negative Differential Conductance Signature
In this paper we present a method for the real-time detection of the bases of
the deoxyribonucleic acid using their signatures in negative differential
conductance measurements. The present methods of electronic detection of
deoxyribonucleic acid bases are based on a statistical analysis because the
electrical currents of the four bases are weak and do not differ significantly
from one base to another. In contrast, we analyze a device that combines the
accumulated knowledge in nanopore and scanning tunneling detection, and which
is able to provide very distinctive electronic signatures for the four bases
Negative Differential Resistance of Electrons in Graphene Barrier
The graphene is a native two-dimensional crystal material consisting of a
single sheet of carbon atoms. In this unique one-atom-thick material, the
electron transport is ballistic and is described by a quantum relativistic-like
Dirac equation rather than by the Schrodinger equation. As a result, a graphene
barrier behaves very differently compared to a common semiconductor barrier. We
show that a single graphene barrier acts as a switch with a very high on-off
ratio and displays a significant differential negative resistance, which
promotes graphene as a key material in nanoelectronics
Time Flow in Graphene and Its Implications on the Cutoff Frequency of Ballistic Graphene Devices
This manuscript deals with time flow in ballistic graphene devices. It is
commonly believed that in the ballistic regime the traversal time of carriers
in gated graphene at normal incidence is just the ratio of the length of the
device and the Fermi velocity. However, we show that the traversal time is much
slower if the influence of metallic contacts on graphene is considered. Even
the transmission at normal incidence becomes smaller than 1, contradicting yet
another common belief. These unexpected effects are due to the transformation
of Schrodinger electrons in the metallic contact into Dirac electrons in
graphene and vice versa. As a direct consequence of these transformations, the
ultimate performance of gated ballistic devices are much lower than expected,
in agreement with experimental results
Extraordinary tunability of high-frequency devices using Hf0.3Zr0.7O2 ferroelectric at very low applied voltages
This paper presents the applications of the Hf0.3Zr0.7O2 ferroelectric with a thickness of 10 nm for tuning high-frequency devices such as filters, phase shifters, and phased antenna arrays in the X band when the low bias voltages in the range −3 V–+3 V are applied. In this respect, we show that a bandpass filter shifts its central frequency located at 10 GHz with 3 GHz, a phase shifter produces a phase difference of about 60 degrees in the X band, while the antenna array formed by two patched antennas is steering its lobe with ±32° at 10 GHz. These results open the way for the tunability of high frequency devices for very low power applications, which represent one of the most challenging issues in applied physics
- …