222 research outputs found
Ab-initio Modeling of CBRAM Cells: from Ballistic Transport Properties to Electro-Thermal Effects
We present atomistic simulations of conductive bridging random access memory
(CBRAM) cells from first-principles combining density-functional theory and the
Non-equilibrium Green's Function formalism. Realistic device structures with an
atomic-scale filament connecting two metallic contacts have been constructed.
Their transport properties have been studied in the ballistic limit and in the
presence of electron-phonon scattering, showing good agreement with
experimental data. It has been found that the relocation of few atoms is
sufficient to change the resistance of the CBRAM by 6 orders of magnitude, that
the electron trajectories strongly depend on the filament morphology, and that
self-heating does not affect the device performance at currents below 1 A.Comment: 6 figures, conferenc
UltralowâPower AtomicâScale Tin Transistor with Gate Potential in Millivolt
After decades of continuous scaling, further advancement of complementary metal-oxide-semiconductor (CMOS) technology across the entire spectrum of computing applications is today limited by power dissipation, which scales with the square of the supply voltage. Here, an atomic-scale tin transistor is demonstrated to perform conductive switching between bistable configurations with on/off potentials â€2.5 mV in magnitude. In addition to the low operation voltage, the channel length of the transistor is determined experimentally and with density-functional theory to be â€1 nm because the atoms instead of electrons are information carriers in this device. The conductance at on-states of the bistable configurations varies between 1.2 G to 197 G (G = 2e h, e stands for the electron charge and h for Planck\u27s constant). Thus, the device can supply driving current from 1 to â375 ”A in magnitude for logic circuits with the drain-source dc voltage at decades of millivolts. The switching frequency of the atomic-scale tin transistor has reached 2047 Hz. Furthermore, the on/off potentials in millivolts can reduce the energy consumption in the interconnects of integrated circuits at least by â400 times. Therefore, the atomic-scale tin transistor has prospects in digital circuits with ultralow-power dissipation and can contribute to the sustainability of modern society
Detection or modulation at 35 Gbit/s with a standard CMOS-processed optical waveguide
Light modulation and detection within a single SOI waveguide is demonstrated at 1550 nm. Multi-functional devices allow simplified transceiver systems. Savings in the number of fabrication steps increase the yield and reduce costs
Coherent terabit communications with microresonator Kerr frequency combs
Optical frequency combs enable coherent data transmission on hundreds of
wavelength channels and have the potential to revolutionize terabit
communications. Generation of Kerr combs in nonlinear integrated microcavities
represents a particularly promising option enabling line spacings of tens of
GHz, compliant with wavelength-division multiplexing (WDM) grids. However, Kerr
combs may exhibit strong phase noise and multiplet spectral lines, and this has
made high-speed data transmission impossible up to now. Recent work has shown
that systematic adjustment of pump conditions enables low phase-noise Kerr
combs with singlet spectral lines. Here we demonstrate that Kerr combs are
suited for coherent data transmission with advanced modulation formats that
pose stringent requirements on the spectral purity of the optical source. In a
first experiment, we encode a data stream of 392 Gbit/s on subsequent lines of
a Kerr comb using quadrature phase shift keying (QPSK) and 16-state quadrature
amplitude modulation (16QAM). A second experiment shows feedback-stabilization
of a Kerr comb and transmission of a 1.44 Tbit/s data stream over a distance of
up to 300 km. The results demonstrate that Kerr combs can meet the highly
demanding requirements of multi-terabit/s coherent communications and thus
offer a solution towards chip-scale terabit/s transceivers
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