Excitonic contributions to the quantum-confined Pockels effect

  • Cortez S.
  • Gentner J.
  • Ivchenko E.
  • Krebs O.
  • Toropov A.
  • Voisin P.

The quantum confined Pockels effect results from the combination of the genuine interface roto-inversion asymmetry and the breakdown of quantum well inversion symmetry due to the applied electric field. It is currently understood in terms of the field-dependent mixing of the heavy and light hole states at the center of ...

Determination of the complex microwave photoconductance of a single quantum dot

  • Bichler M.
  • Blick R.
  • Kotthaus J.
  • Qin H.
  • Simmel F.
  • Wegscheider W.

A small quantum dot containing approximately 20 electrons is realized in a two-dimensional electron system of an AlxGa1-xAs/GaAs heterostructure. Conventional transport and microwave spectroscopy reveal the dot's electronic structure. By applying a coherently coupled two-source technique, we are able to determine the complex microwave-induced tunnel current. The amplitude of this ...

Hybrid polymer/silica vertical coupler switch with <-32dB polarisation-independent crosstalk

  • Bauer J.
  • Bauer M.
  • Keil N.
  • Losch K.
  • Satzke K.
  • Schneider J.
  • Wirth J.
  • Wischmann W.
  • Yao H.
  • Zawadzki C.

A modified hybrid polymer/silica 1 x 2 vertical coupler su itch (VCS) with a polymer gap layer and a refractive index contrast of 0.008 has been designed. fabricated and characterised. The VCS exhibits low loss, low crosstalk, low switching power, and polarisation insensitivity. Using the 1 x 2 VCS as ...

Quantum-cascade laser measurements of stratospheric methane and nitrous oxide

  • Baillargeon J.
  • Capasso F.
  • Cho A.
  • Flesch G.
  • Gmachl C.
  • Hutchinson A.
  • May R.
  • Scott D.
  • Sivco D.
  • Swanson J.
  • Webster C.
  • Woodward W.

A tunable quantum-cascade (QC) laser has been flown on NASA's ER-2 high-altitude aircraft to produce the first atmospheric gas measurements with this newly invented device, an important milestone in the QC laser's future planetary, industrial, and commercial applications. Using a cryogenically cooled QC laser during a series of 20 aircraft ...

Chemical ordering in AlGaN alloys grown by molecular beam epitaxy

  • Chu S.
  • Iliopoulos E.
  • Ludwig K.
  • Moustakas T.

Aluminum gallium nitride alloys were grown by molecular beam epitaxy and their film composition, structure, and microstructure were investigated by Rutherford backscattering spectroscopy, atomic force microscopy, x-ray diffraction, and transmission electron microscopy. It was found that the ratio of group-III to group-V fluxes influences the relative incorporation of gallium and ...

Geometric magnetic frustration in Ba2Sn2Ga3ZnCr7O22: A two-dimensional spinel based Kagome lattice

  • Cava R.
  • Gao X.
  • Hagemann I.
  • Huang Q.
  • Ramirez A.

The properties of a two-dimensional geometrically frustrated magnetic material based on the Kagome net, Ba2Sn2ZnGa3Cr7O22, are reported. The Kagome net is fully filled with magnetic ions. A Curie Weiss theta theta (W) = -312 K is found with a spin glass transition at approximately 1.5 K, indicating strong geometrical magnetic ...

A primer on using PIN diodes in VCAs - Part 2 of this tutorial discusses the pi-configured PIN-diode approach to implement a voltage-controlled attenuator for microwave applications.

  • Fei L.
  • Waugh R.

There are many ways to implement a voltage-controlled attenuator (VCA), but it typically involves the use of some variable-impedance device. This variable impedance device can be a metal-semiconductor field-effect transistor (MESFET) operating as a voltage-variable resistance in its linear region, or it can be a PIN diode operating as a ...

Modeling of direct tunneling and surface roughness effects on C-V characteristics of ultra-thin gate MOS capacitors

  • Ma Y.
  • Oates A.
  • Yuan J.
  • Zhang J.

Effects of direct tunneling and surface roughness on the capacitance-voltage characteristics of ultra-thin gate deep submicron MOS transistors have been studied. An improved equivalent circuit model to account for surface roughness and direct tunneling on the ultra-thin gate MOS capacitors in a unified manner is proposed. The capacitance subject to ...

A three-dimensional nonlinear analysis of electromigration-induced resistance change and Joule heating in microelectronic interconnects

  • Kang S.
  • Shin E.

This paper reports a three-dimensional nonlinear numerical model developed for the deep submicron interconnects that carry high current densities in integrated circuits. This model can solve a thermoelectrically coupled field to analyze resistance variation and Joule heating as a function of electromigration-induced voiding in various interconnect structures. As a result, ...

Self-aligned process for emitter- and base-regrowth GaNHBTs and BJTs

  • Abernathy C.
  • Chu S.
  • Dang G.
  • Han J.
  • Hobson W.
  • Lee J.
  • Lee K.
  • Lopata J.
  • Pearton S.
  • Ren F.
  • Zhang A.

The development of a self-aligned fabrication process for small emitter contact area (2, x 4 mum(2)) GaN/AlGaN heterojunction bipolar transistors and GaN bipolar junction transistors is described. The process features dielectric-spacer sidewalls, low damage dry etching and selected-area regrowth of p-GaAs(C) on the base contact or n-GaN/ AlGaN on the ...

From Schrodinger's equation to the quantum search algorithm

  • Grover L.

The quantum search algorithm is a technique for searching N possibilities in only O(rootN) steps. Although the algorithm itself is widely known, not so well known is the series of steps that first led to it, these are quite different from any of the generally known forms of the algorithm. ...

Epitactic textures of fcc Al on icosahedral Al-Pd-Mn quasicrystal

  • Bolliger B.
  • Dmitrienko V.
  • Erbudak M.
  • Kortan A.
  • Luscher R.
  • Nissen H.

An aluminum film is deposited on the fivefold-symmetric surface of icosahedral Al-Pd-Mn quasicrystal. Its orientation with respect to the bulk structure is studied using low-energy electron diffraction. It is found that Al nanocrystals grow in the face-centered cubic structure in five different sets of domains composing the film, and that ...

A large deviations approach to the transient of the Erlang loss model

  • Mandjes M.
  • Ridder A.

This paper deals with the transient behavior of the Erlang loss model. After scaling both arrival rate and number of trunks, an asymptotic analysis of the blocking probability is given. Apart from that, the most likely path to blocking is given. Compared to Shwartz and Weiss {[}Large Deviations for Performance ...

In vivo intracellular recording and perturbation of persistent activity in a neural integrator

  • Aksay E.
  • Baker R.
  • Gamkrelidze G.
  • Seung H.
  • Tank D.

To investigate the mechanisms of persistent neural activity, we obtained in vivo intracellular recordings from neurons in an oculomotor neural integrator of the goldfish during spontaneous saccades and fixations. Persistent changes in firing rate following saccades were associated with step changes in interspike membrane potential that were correlated with changes ...

A comparison of early stage hot carrier degradation behaviour in 5 and 3 V sub-micron low doped drain metal oxide semiconductor field effect transistors

  • De Souza M.
  • Manhas S.
  • Narayanan E.
  • Oates A.
  • Wang J.

This paper reports the early stage of de hot carrier degradation behaviour of n-channel low doped drain metal oxide semiconductor field effect transistors in a range of deep sub-micron technologies. A deviation from the normally observed power-law expression t{''} at short time scales is revealed. In addition, under V-G = ...

Linear and nonlinear operation of a time-to-space processor

  • Fainman Y.
  • Marom D.
  • Panasenko D.
  • Sun P.

The operational characteristics of a time-to-space processor based on three-wave mixing for instantaneous imaging of ultrafast waveforms are investigated. We assess the effects of various system parameters on the processor's important attributes: time window of operation and signal conversion efficiency. Both linear and nonlinear operation regimes are considered, with use ...

Initiation and propagation of calcium-dependent action potentials in a coupled network of olfactory interneurons

  • Denk W.
  • Flores J.
  • Gelperin A.
  • Wang J.

Coherent oscillatory electrical activity and apical-basal wave propagation have been described previously in the procerebral (PC) lobe, an olfactory center of the terrestrial slug Limax maximus. In this study, we investigate the physiological basis of oscillatory activity and wave propagation in the PC lobe. Calcium green dextran was locally deposited ...

Redundancy strategies for a high splitting optically amplified passive optical network

  • Martin C.
  • Mercinelli R.
  • Phillips A.
  • Qiu X.
  • Senior J.
  • Vaes P.
  • Valvo M.
  • Van Deventer M.
  • Vetter P.

High splitting, optically amplified, passive optical networks (SuperPONs) are investigated in terms of redundancy provision and protection mechanisms. Options for redundancy, including the important special case of dual homing, are detailed, and it is determined as to which of these options (duplication of the feeder and first distribution section, and ...