Pages
- 1
- 2
- document
-
Van der Valk, N.C.J. (author), Planken, P.C.M. (author)We report on a method to obtain a subwavelength resolution in terahertz time-domain imaging. In our method, a sharp copper tip is used to locally distort and concentrate the THz electric field. The distorted electric field, present mainly in the near field of the tip, is electro-optically measured in an (100) oriented GaP crystal. By raster...journal article 2002
- document
-
De Franceschi, S. (author), Van Dam, J.A. (author), Bakkers, E.P.A.M. (author), Feiner, L.F. (author), Gurevich, L. (author), Kouwenhoven, P. (author)We report on the fabrication and electrical characterization of field-effect devices based on wire-shaped InP crystals grown from Au catalyst particles by a vapor–liquid–solid process. Our InP wires are n-type doped with diameters in the 40–55-nm range and lengths of several micrometers. After being deposited on an oxidized Si substrate, wires...journal article 2003
- document
-
Elzerman, J.M. (author), Hanson, R. (author), Willems van Beveren, L.H. (author), Vandersypen, L.M.K. (author), Kouwenhoven, L.P. (author)We demonstrate a method for measuring the discrete energy spectrum of a quantum dot connected very weakly to a single lead. A train of voltage pulses applied to a metal gate induces tunneling of electrons between the quantum dot and a reservoir. The effective tunnel rate depends on the number and nature of the energy levels in the dot made...journal article 2004
- document
-
Zhang, L.X. (author), Leburton, J.P. (author), Hanson, R. (author), Kouwenhoven, L.P. (author)We show that the design of a quantum point contact adjacent to a quantum dot can be optimized to produce maximum sensitivity to single-electron charging in the quantum dot. Our analysis is based on the self-consistent solution of coupled three-dimensional Kohn-Sham and Poisson equations for the quantum circuit. We predict a detection sensitivity...journal article 2004
- document
-
Vandersypen, L.M.K. (author), Elzerman, J.M. (author), Schouten, R.N. (author), Willems van Beveren, L.H. (author), Hanson, R. (author), Kouwenhoven, L.P. (author)We observe individual tunnel events of a single electron between a quantum dot and a reservoir, using a nearby quantum point contact (QPC) as a charge meter. The QPC is capacitively coupled to the dot, and the QPC conductance changes by about 1% if the number of electrons on the dot changes by one. The QPC is voltage biased and the current is...journal article 2004
- document
-
Sim, E. (author), Beckers, J. (author), De Leeuw, S. (author), Thorpe, M. (author), Ratner, M.A. (author)We introduce a simple semiempirical anharmonic Kirkwood–Keating potential to model AxB1?xC-type semiconductors. The potential consists of the Morse strain energy and Coulomb interaction terms. The optical constants of pure components, AB and BC, were employed to fit the potential parameters such as bond-stretching and -bending force constants,...journal article 2005
- document
-
Van der Heijden, R. (author), Carlström, C.F. (author), Snijders, J.A.P. (author), Van der Heijden, R.W. (author), Karouta, F. (author), Nötzel, R. (author), Salemink, H.W.M. (author), Kjellander, B.K.C. (author), Bastiaansen, C.W.M. (author), Broer, D.J. (author), Van der Drift, E. (author)Polymer filling of the air holes of indium-phosphide-based two-dimensional photonic crystals is reported. After infiltration of the holes with a liquid monomer and solidification of the infill in situ by thermal polymerization, complete filling is proven using scanning electron microscopy. Optical transmission measurements of a filled photonic...journal article 2006
- document
-
Dorenbos, P. (author), Van der Kolk, E. (author)Knowledge from lanthanide spectroscopy on wide band gap (6–10?eV) inorganic compounds is used to understand and predict optical and electronic properties of the lanthanides in the III-V semiconductor GaN. For the first time the location of the 4fn ground state energy of each divalent and trivalent lanthanide ion relative to the valence and...journal article 2006
- document
-
Ghatak, K.P. (author), Bhattacharya, S. (author), Bhowmik, S. (author), Benedictus, R. (author), Choudhury, S. (author)We study thermoelectric power under strong magnetic field (TPM) in carbon nanotubes (CNTs) and quantum wires (QWs) of nonlinear optical, optoelectronic, and related materials. The corresponding results for QWs of III-V, ternary, and quaternary compounds form a special case of our generalized analysis. The TPM has also been investigated in QWs of...journal article 2008
- document
-
Ghatak, K.P. (author), Bhattacharya, S. (author), Bhowmik, S. (author), Benedictus, R. (author), Choudhury, S. (author)We study the Einstein relation for the diffusivity to mobility ratio (DMR) in quantum wires (QWs) of III-V, ternary, and quaternary materials in the presence of light waves, whose unperturbed energy band structures are defined by the three band model of Kane. It has been found, taking n-InAs, n-InSb, n-Hg1?xCdxTe, n-In1?xGaxAsyP1?y lattice...journal article 2008
- document
-
Caro, J. (author), Roeling, E.M. (author), Rong, B. (author), Nguyen, H.M. (author), Van der Drift, E.W.J.M. (author), Rogge, S. (author), Karouta, F. (author), Van der Heijden, R.W. (author), Salemink, H.W.M. (author)A high-contrast-ratio (30 dB) photonic band gap in the near-infrared transmission of hole-type GaN two-dimensional photonic crystals (PhCs) is reported. These crystals are deeply etched in a 650 nm thick GaN layer grown on sapphire. A comparison of the measured spectrum with finite difference time domain simulations gives quantitative agreement...journal article 2008
- document
-
Carlström, C.F. (author), Van der Heijden, R. (author), Andriesse, M.S.P. (author), Karouta, F. (author), Van der Heijden, R.W. (author), Van der Drift, E.W.J.M. (author), Salemink, H.W.M. (author)An extensive investigation has been performed on inductively coupled plasma etching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl2 with the addition of N2 or O2 for sidewall passivation. The influence of different process parameters such...journal article 2008
- document
-
Perinetti, U. (author), Akopian, N. (author), Samsonenko, Y.B. (author), Bouravleuv, A.D. (author), Cirlin, G.E. (author), Zwiller, V. (author)We report on optical studies of single InAs quantum dots grown on vicinal GaAs(001) surfaces. To ensure low quantum dot density and appropriate size, we deposit InAs layers 1.4 or 1.5 ML thick, thinner than the critical thickness for Stranski–Krastanov quantum dot formation. These dots show sharp and bright photoluminescence. Lifetime...journal article 2009
- document
-
Kicken, H.H.J.E. (author), Barbu, I. (author), Van der Heijden, R.W. (author), Karouta, F. (author), Nötzel, R. (author), Van der Drift, E. (author), Salemink, H.W.M. (author)The photonic properties of two classes of wavelength-sized cavities are reported for deeply etched InP/InGaAsP/InP planar photonic crystals. The high aspect, deeply etched structures are studied as potential building blocks for nonmembrane type photonic devices in standard InP photonic integrated circuits. The first class consists of cavities of...journal article 2009
- document
-
Scheffler, M. (author), Nadj-Perge, S. (author), Kouwenhoven, L.P. (author), Borgström, M.T. (author), Bakkers, E.P.A.M. (author)Electrical conductance through InAs nanowires is relevant for electronic applications as well as for fundamental quantum experiments. Here, we employ nominally undoped, slightly tapered InAs nanowires to study the diameter dependence of their conductance. By contacting multiple sections of each wire, we can study the diameter dependence within...journal article 2009
- document
-
Van Weert, M.H.M. (author), Den Heijer, M. (author), Van Kouwen, M.P. (author), Algra, R.E. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, L.P. (author), Zwiller, V. (author)We report voltage dependent photoluminescence experiments on single indium arsenide phosphide (InAsP) quantum dots embedded in vertical surround-gated indium phosphide (InP) nanowires. We show that by tuning the gate voltage, we can access different quantum dot charge states. We study the anisotropic exchange splitting by polarization analysis,...journal article 2010
- document
-
Akopian, N. (author), Perinetti, U. (author), Wang, L. (author), Rastelli, A. (author), Schmidt, O.G. (author), Zwiller, V. (author)We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D2 transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum dot photoluminescence in a rubidium vapor. This...journal article 2010
- document
-
Van Kouwen, M.P. (author), Van Weert, M.H.M. (author), Reimer, M.E. (author), Akopian, N. (author), Perinetti, U. (author), Algra, R.E. (author), Bakkers, E.P.A.M. (author), Kouwenhoven, L.P. (author), Zwiller, V. (author)We report InP nanowire photodetectors with a single InAsP quantum dot as light absorbing element. With excitation above the InP band gap, the nanowire photodetectors are efficient (quantum efficiency of 4%). Under resonant excitation of the quantum dot, the photocurrent amplitude depends on the linear polarization direction of the incident light...journal article 2010
- document
-
Dorenbos, S.N. (author), Sasakura, H. (author), Van Kouwen, M.P. (author), Akopian, N. (author), Adachi, S. (author), Namekata, N. (author), Jo, M. (author), Motohisa, J. (author), Kobayashi, Y. (author), Tomioka, K. (author), Fukui, T. (author), Inoue, S. (author), Kumano, H. (author), Natarajan, C.M. (author), Hadfield, R.H. (author), Zijlstra, T. (author), Klapwijk, T.M. (author), Zwiller, V. (author), Suemune, I. (author)We report the experimental demonstration of single-photon and cascaded photon pair emission in the infrared, originating from a single InAsP quantum dot embedded in a standing InP nanowire. A regular array of nanowires is fabricated by epitaxial growth on an electron-beam patterned substrate. Photoluminescence spectra taken on single quantum...journal article 2010
- document
-
Schins, J.M. (author)The retrieval of the primary (subpicosecond) photoproducts in small-band two-dimensional time-domain terahertz spectroscopy has succeeded only in a few model systems, due to the complicated correlation between the two time parameters. We show that the nature of the primary photoproducts is revealed upon differentiating the measured time-domain...journal article 2010
Pages
- 1
- 2