The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Phaedon Avouris - One of the best experts on this subject based on the ideXlab platform.

  • spatially resolved Electrostatic Potential and photocurrent generation in carbon nanotube array devices
    ACS Nano, 2012
    Co-Authors: Michael Engel, Mathias Steiner, R S Sundaram, Ralph Krupke, Alexander A Green, Mark C Hersam, Phaedon Avouris
    Abstract:

    We have used laser-excited photocurrent microscopy to map the internal Electrostatic Potential profile of semiconducting single-walled carbon nanotube (S-SWCNT) array devices with a spatial resolution of 250 nm. The measurements of S-SWCNTs on optically transparent samples provide new insights into the physical principles of device operation and reveal performance-limiting local heterogeneities in the Electrostatic Potential profile not observable with other imaging techniques. The experiments deliver photocurrent images from the underside of the S-SWCNT–metal contacts and thus enable the direct measurement of the charge carrier transfer lengths at the palladium–S-SWCNT and aluminum–S-SWCNT interfaces. We use the experimental results to formulate design rules for optimized layouts of S-SWCNT-based photovoltaic devices. Furthermore, we demonstrate the external control of the Electrostatic Potential profile in S-SWCNT array devices equipped with local metal gates.

  • Understanding the Variation of the Electrostatic Potential along a Biased Molecular Wire
    Nano Letters, 2003
    Co-Authors: Norton D. Lang, Phaedon Avouris
    Abstract:

    We present first principles calculations of the electronic structure, conductance, and Electrostatic Potential profile of a biased molecular wire. Metal-molecule charge transfer, bias-induced polarization of the wire, electron backscattering, and intrawire screening affect the Electrostatic Potential along the wire. Substituting a single atom in the wire can drastically change the Potential distribution.

Xiang Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Surface Electrostatic Potential transformation of nanodiamond induced by graphitization
    The Journal of chemical physics, 2012
    Co-Authors: Tao Yang, Xiang Zhao
    Abstract:

    The surface Electrostatic Potential of raw nanodiamonds is implied to be altered permanently during in the spontaneously occurred graphitization process by recent reports. With all-electron ab initio density functional theory methods, the intrinsic effect of graphitization on the Electrostatic Potential of nanodiamonds is investigated. It is exposed that while the graphitization process goes on, the dangling bonds on the (111) surface transfer into the inner side and subsequently the surface Potential changes from negative to positive. Our results may be of great help in understanding the various Electrostatic properties of nanodiamonds.

Dennis R. Salahub - One of the best experts on this subject based on the ideXlab platform.

  • Topological analysis of the molecular Electrostatic Potential
    The Journal of Chemical Physics, 1999
    Co-Authors: Martin Leboeuf, Andreas M. Köster, Karl Jug, Dennis R. Salahub
    Abstract:

    The topology of the molecular Electrostatic Potential of 18 molecules, calculated in the framework of Kohn–Sham density functional theory, is studied. For the location of the different kinds of critical points a newly developed search algorithm is applied. A chemical interpretation of the critical points in terms of lone pairs, π bonds, hybrid orbitals and other electronic structure elements is suggested. A Poincare–Hopf relationship for the molecular Electrostatic Potential is derived, connecting electronic structure elements and Electrostatic reactivity via the topology of the molecular Electrostatic Potential.

Mark A Ratner - One of the best experts on this subject based on the ideXlab platform.

  • molecular wire conductance Electrostatic Potential spatial profile
    Journal of Chemical Physics, 2000
    Co-Authors: Vladimiro Mujica, Adrian E Roitberg, Mark A Ratner
    Abstract:

    We have studied the effect of the Electrostatic Potential on the current across a one-dimensional tight-binding molecular wire by solving self-consistently the Poisson and Schrodinger equations. The results indicate that Electrostatic effects on the current are very important in the nonlinear regime. They manifest themselves through a strong variation of the voltage drop in the interfacial region compared to the linear ramp expected in the absence of charge in the wire and also in the nature of the current–voltage characteristics.

Rafal E Duninborkowski - One of the best experts on this subject based on the ideXlab platform.

  • towards quantitative Electrostatic Potential mapping of working semiconductor devices using off axis electron holography
    Ultramicroscopy, 2015
    Co-Authors: Sadegh Yazdi, Takeshi Kasama, Marco Beleggia, Maryam Samaie Yekta, David W Mccomb, A C Twitchettharrison, Rafal E Duninborkowski
    Abstract:

    Pronounced improvements in the understanding of semiconductor device performance are expected if Electrostatic Potential distributions can be measured quantitatively and reliably under working conditions with sufficient sensitivity and spatial resolution. Here, we employ off-axis electron holography to characterize an electrically-biased Si p–n junction by measuring its Electrostatic Potential, electric field and charge density distributions under working conditions. A comparison between experimental electron holographic phase images and images obtained using three-dimensional Electrostatic Potential simulations highlights several remaining challenges to quantitative analysis. Our results illustrate how the determination of reliable Potential distributions from phase images of electrically biased devices requires Electrostatic fringing fields, surface charges, specimen preparation damage and the effects of limited spatial resolution to be taken into account.