APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

16 Mar 2009

Volume 94, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 111101 (2009); http://dx.doi.org/10.1063/1.3097278 (3 pages)

Ling Lu, Adam Mock, Tian Yang, Min Hsiung Shih, Eui Hyun Hwang, Mahmood Bagheri, Andrew Stapleton, Stephen Farrell, John O’Brien, and P. Daniel Dapkus
Enlarge Image | Read More
Page 3 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Weak exchange effect and large refrigerant capacity in a bulk metallic glass Gd0.32Tb0.26Co0.20Al0.22

Yongsheng Liu, Jincang Zhang, Youquan Wang, Yanyan Zhu, Zhenglong Yang, Jing Chen, and Shixun Cao

Appl. Phys. Lett. 94, 112507 (2009); http://dx.doi.org/10.1063/1.3097237 (3 pages) | Cited 15 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic behavior and refrigeration capacity of Gd0.32Tb0.26Co0.20Al0.22, a bulk metallic glass (BMG) fabricated by a copper-mold suck-casting method, are investigated. The Curie temperature increases from 79 K at 200 Oe to 95 K at 50 000 Oe. A weak exchange field of 25 T in the BMG system, caused by the strong disorder, is derived by the mean-field approximation. The maximum magnetic entropy change (8.02 J kg−1 K−1) and the refrigerant capacity (642 J kg−1) for 5 T indicate the BMG has the better refrigerant efficiency compared to known magnetic refrigerants.
Show PACS
75.30.Et Exchange and superexchange interactions
75.30.Sg Magnetocaloric effect, magnetic cooling
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.50.Cc Other ferromagnetic metals and alloys

Electrostatically tunable magnetoelectric inductors with large inductance tunability

J. Lou, D. Reed, M. Liu, and N. X. Sun

Appl. Phys. Lett. 94, 112508 (2009); http://dx.doi.org/10.1063/1.3103273 (3 pages) | Cited 18 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A class of electrostatically tunable inductors with multiferroic composite cores consisting of Metglas/lead zirconate titanate/Metglas was demonstrated. These magnetoelectric inductors exhibit a large tunable inductance range ΔL/Lmin of up to 450%, together with improved quality factors. Such tunability of inductance and quality factor was due to a strong magnetoelectric coupling in the multiferroic composite core, which led to electric field induced permeability change. The concept of tuning inductance by electric field using multiferroic composite materials leads to a class of compact tunable inductors with minimum power consumption.
Show PACS
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
84.32.Hh Inductors and coils; wiring
75.80.+q Magnetomechanical effects, magnetostriction

Tunable ferromagnetic resonance in NiFe nanowires with strong magnetostatic interaction

Xiaoming Kou, Xin Fan, Hao Zhu, and John Q. Xiao

Appl. Phys. Lett. 94, 112509 (2009); http://dx.doi.org/10.1063/1.3103562 (3 pages) | Cited 15 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetic materials with tunable ferromagnetic resonant (FMR) frequencies are highly desirable in microwave devices. In this manuscript, we demonstrate that the natural FMR of Ni90Fe10 nanowire array can be tuned continuously from 8.2 to 11.7 GHz by choosing different remanent states. Theoretical model based on magnetostatic interaction among nanowires has been developed to explain the observed phenomena.
Show PACS
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
back to top
RSS Feeds

High sensitivity microwave characterization of organic molecule solutions of nanoliter volume

E. N. Shaforost, N. Klein, S. A. Vitusevich, A. A. Barannik, and N. T. Cherpak

Appl. Phys. Lett. 94, 112901 (2009); http://dx.doi.org/10.1063/1.3097015 (3 pages) | Cited 5 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A microwave resonator composed of a sapphire cylinder and a quartz plate with a 400 nl cavity was developed for the determination of the complex permittivity of liquids at 10 GHz. This sensor was calibrated over a wide range of values for real and imaginary parts of permittivity. The measured resonator losses induced by the liquid were found to be proportional to the dipole relaxation time of the liquid molecules, as predicted by perturbation theory. Our analysis of weight concentration and temperature dependence of the measured inverse quality factor revealed a sensitivity of about 0.1% for aqueous solutions of glucose.
Show PACS
77.22.Ch Permittivity (dielectric function)
82.80.-d Chemical analysis and related physical methods of analysis
77.22.Gm Dielectric loss and relaxation
64.75.-g Phase equilibria

Magnetoelectric effect of (100−x)BaTiO3–(x)NiFe1.98O4 (x = 20–80 wt %) particulate nanocomposites

G. Sreenivasulu, V. Hari Babu, G. Markandeyulu, and B. S. Murty

Appl. Phys. Lett. 94, 112902 (2009); http://dx.doi.org/10.1063/1.3095600 (3 pages) | Cited 7 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetoelectric (100−x)BaTiO3–(x)NiFe1.98O4 (x = 20, 40, 60, and 80 wt %) particulate composites have been prepared and the effects of size and interface are studied through microscopy measurements. Large magnetoelectric voltage coefficient (αE) values accompanied by large piezoelastic coefficient, large magnetostrictive strain coefficient, and an adequate interface contact between the magnetic and electric phases were observed in these nanocomposites. The nanocomposite with x = 40 has an αE value of 252 mV cm−1 Oe−1, which is the largest value for any particulate magnetoelectric composite, based on the available open literature.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
77.84.Lf Composite materials
81.07.Bc Nanocrystalline materials

Nd-doped BiFeO3 ceramics with antipolar order

S. Karimi, I. M. Reaney, I. Levin, and I. Sterianou

Appl. Phys. Lett. 94, 112903 (2009); http://dx.doi.org/10.1063/1.3097222 (3 pages) | Cited 34 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Bi1−xNdxFeO3 (0 ≤ x ≤ 0.2) ceramics have been investigated using x-ray diffraction (XRD) and electron diffraction (ED). XRD patterns for x ≤ 0.1 were consistent with rhombohedral BiFeO3, whereas those for x = 0.15 and x = 0.2 exhibited peak splitting and superlattice reflections representative of orthorhombic, antiferroelectric PbZrO3. ED for the latter samples confirmed the presence of ¼(hk0) superlattice reflections typical of a PbZrO3-like structure but additional superlattice reflections were observed at ¼(00l) yielding a √2a,2√2a,4a (where a is the pseudocubic lattice parameter) unit cell. The transition from rhombohedral BiFeO3 to the PbZrO3-like structure implies a modification from polar to antipolar behavior.
Show PACS
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
61.05.J- Electron diffraction and scattering
64.70.K- Solid-solid transitions
77.80.B- Phase transitions and Curie point
61.05.C- X-ray diffraction and scattering
61.66.Fn Inorganic compounds

Improved leakage and ferroelectric properties of Mn and Ti codoped BiFeO3 thin films

T. Kawae, Y. Terauchi, H. Tsuda, M. Kumeda, and A. Morimoto

Appl. Phys. Lett. 94, 112904 (2009); http://dx.doi.org/10.1063/1.3098408 (3 pages) | Cited 54 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polycrystalline BiFeO3 (BFO), Ti-doped BFO, Mn-doped BFO, and (Mn, Ti)-codoped BFO (BFMT) thin films were fabricated on Pt/SrTiO3 (100) substrate by pulsed laser deposition. Observed leakage current behavior in those ion-doped BFO films indicated the dominance of space-charge-limited current in the high electric field region. The leakage current of the BFMT film was much reduced in relation to the other films due to the formation of deep traps. In the BFMT film, well saturated P-E hysteresis curves were observed. Remanent polarization and coercive field for maximum electric field of 2100 kV/cm were 75 μC/cm2 and 310 kV/cm, respectively.
Show PACS
77.22.Ej Polarization and depolarization
81.15.Fg Pulsed laser ablation deposition
77.55.-g Dielectric thin films
77.22.Jp Dielectric breakdown and space-charge effects
77.80.Dj Domain structure; hysteresis

Quantitative evaluation of local domain patterns in [110] poled Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 single crystal using a polarized Raman microprobe

Wanyin Ge, Wenliang Zhu, Yanxue Tang, and Giuseppe Pezzotti

Appl. Phys. Lett. 94, 112905 (2009); http://dx.doi.org/10.1063/1.3103274 (3 pages) | Cited 3 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An experimental/computational procedure was presented to quantitatively analyze by polarized Raman spectroscopy (PRS) unknown domain textures in [110] poled Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 single crystal. The three-dimensional domain orientation was described in terms of three Euler angles in space, and an Euler matrix was employed to transform the axial coordinates detected at the molecular scale into the laboratory coordinate frame. Raman spectral intensity of selected bands belonging to the Ag and Eg vibrational modes varied as a function of polarization geometry and rotation angle about the [110] direction. Periodic functions, which precisely fit experimental data, could be located to describe such dependences, according to theoretical considerations. The reliability and the efficiency of PRS characterization were demonstrated and the angles of domain orientation were observed and mapped at the microscopic scale.
Show PACS
77.80.Dj Domain structure; hysteresis
63.20.-e Phonons in crystal lattices
78.30.Hv Other nonmetallic inorganics
back to top
RSS Feeds

Metallization induced by nitrogen atom adsorption on silicon nanofilms and nanowires

X. B. Yang and R. Q. Zhang

Appl. Phys. Lett. 94, 113101 (2009); http://dx.doi.org/10.1063/1.3098455 (3 pages) | Cited 2 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
First-principles calculations on the electronic properties of silicon nanofilms and nanowires that were adsorbed with nitrogen atoms on (110) facets revealed the formation of N–Si–N–Si chains, which causes the conduction and valence bands to intersect and metallizes the system. The interaction between the nitrogen and silicon atoms on the surface was found to induce energy bands near the Fermi level. The metallic electronic states induced by surface adsorption could be expected to significantly improve the conducting properties of the Si nanostructures due to their large surface-to-volume ratio and thus has great implications for SiNWs in nanoelectronic applications.
Show PACS
68.43.Mn Adsorption kinetics
68.55.ag Semiconductors
71.20.Mq Elemental semiconductors
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices

Surface modification of highly ordered TiO2 nanotube arrays for efficient photoelectrocatalytic water splitting

Chin-Jung Lin, Yen-Tien Lu, Chang-Hsun Hsieh, and Shu-Hua Chien

Appl. Phys. Lett. 94, 113102 (2009); http://dx.doi.org/10.1063/1.3099338 (3 pages) | Cited 21 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An efficient visible-light-sensitive heterostructure photoanode of CdS nanoparticles/ZnO shell/TiO2 nanotube (CdS/ZnO–TiNT) arrays were investigated for solar water splitting. Highly ordered arrays of TiNT were grown vertically on Ti foil by electrochemical anodization. Both aqueous solution routes were used in turn to coat a thin recombination barrier of ZnO shell and narrow band gap CdS nanoparticles to the surface of the TiNT arrays. As a result of strong absorption within solar spectrum and effective suppression of electron-hole pair recombination in CdS/ZnO–TiNT arrays, a significant improvement in solar-to-hydrogen conversion efficiency from 0.39% to 1.30% was obtained.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
82.50.Hp Processes caused by visible and UV light
82.45.Jn Surface structure, reactivity and catalysis
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
61.46.Fg Nanotubes
82.45.Cc Anodic films

Tomographic study of atomic-scale redistribution of platinum during the silicidation of Ni0.95Pt0.05/Si(100) thin films

Praneet Adusumilli, Lincoln J. Lauhon, David N. Seidman, Conal E. Murray, Ori Avayu, and Yossi Rosenwaks

Appl. Phys. Lett. 94, 113103 (2009); http://dx.doi.org/10.1063/1.3099970 (3 pages) | Cited 4 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Atom-probe tomography was utilized to study the distribution of Pt after silicidation of a solid-solution Ni0.95Pt0.05 thin film on Si(100). Direct evidence of Pt short-circuit diffusion via grain boundaries, Harrison’s type-B regime, is found after silicidation to form (Ni0.99Pt0.01)Si. This underscores the importance of interfacial phenomena for stabilizing this low-resistivity phase, providing insights into the modification of NiSi texture, grain size, and morphology caused by Pt. Platinum segregates at the (Ni0.99Pt0.01)Si/Si(100) interface, which may be responsible for the increased resistance of (Ni0.99Pt0.01)Si to agglomeration. The relative shift in work function between as-deposited and annealed states is greater for Ni(Pt)Si than for NiSi.
Show PACS
81.05.Hd Other semiconductors
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
73.40.Ns Metal-nonmetal contacts
73.30.+y Surface double layers, Schottky barriers, and work functions
68.55.jm Texture
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.Fx Diffusion; interface formation

Solution processed large area field effect transistors from dielectrophoreticly aligned arrays of carbon nanotubes

Paul Stokes, Eliot Silbar, Yashira M. Zayas, and Saiful I. Khondaker

Appl. Phys. Lett. 94, 113104 (2009); http://dx.doi.org/10.1063/1.3100197 (3 pages) | Cited 11 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate solution processable large area field effect transistors (FETs) from aligned arrays of carbon nanotubes (CNTs). Commercially available, surfactant free CNTs suspended in aqueous solution were aligned between source and drain electrodes using ac dielectrophoresis technique. After removing the metallic nanotubes using electrical breakdown, the devices displayed p-type behavior with on-off ratios up to ∼ 2×104. The measured field effect mobilities are as high as 123 cm2/V s, which is three orders of magnitude higher than typical solution processed organic FET devices.
Show PACS
85.30.Tv Field effect devices
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems
85.35.Kt Nanotube devices
81.07.De Nanotubes

Controlled growth of one-dimensional clusters of molybdenum atoms using double-walled carbon nanotube templating

Yousheng Tao, Hiroyuki Muramatsu, Takuya Hayashi, Yoong Ahm Kim, Daisuke Shimamoto, Morinobu Endo, Katsumi Kaneko, Mauricio Terrones, and Mildred S. Dresselhaus

Appl. Phys. Lett. 94, 113105 (2009); http://dx.doi.org/10.1063/1.3089576 (3 pages) | Cited 4 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the controlled growth of one-dimensional clusters of molybdenum atoms inside the inner cores of double-walled carbon nanotubes. A combined characterization including high resolution transmission electron microscopy, nitrogen adsorption measurement at 77 K, x-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric analysis reveals that the growth of one-dimensional Mo clusters can be controlled by varying the reaction conditions. The products have specific surface areas of 360–480 m2 g−1, and their characteristic properties are attributed to the presence of Mo cluster, which affect the electronic structure and can be exploited for the development of nanotube electronic devices.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.67.Ch Nanotubes
79.60.Jv Interfaces; heterostructures; nanostructures
81.07.Bc Nanocrystalline materials
78.30.Na Fullerenes and related materials

P-type electrical, photoconductive, and anomalous ferromagnetic properties of Cu2O nanowires

L. Liao, B. Yan, Y. F. Hao, G. Z. Xing, J. P. Liu, B. C. Zhao, Z. X. Shen, T. Wu, L. Wang, J. T. L. Thong, C. M. Li, W. Huang, and T. Yu

Appl. Phys. Lett. 94, 113106 (2009); http://dx.doi.org/10.1063/1.3097029 (3 pages) | Cited 19 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cu2O nanowires are synthesized by reduction of CuO nanowires with hydrogen gas. Strong green photoluminescence dominated by band-edge emission is observed. Field effect transistors fabricated from individual Cu2O nanowires present high on-off ratio (>106) and high mobility (>95 cm2/V s). Furthermore, the device demonstrates a fast photoelectric response to blue illumination in air at room temperature. In addition, anomalous ferromagnetism appears in Cu2O nanowires, which may originate from the defects in Cu2O nanowires. This work shows the application potentials of the Cu2O nanowires, especially in an electrical and photonic device.
Show PACS
73.63.-b Electronic transport in nanoscale materials and structures
81.07.-b Nanoscale materials and structures: fabrication and characterization
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
78.55.Hx Other solid inorganic materials
72.20.Fr Low-field transport and mobility; piezoresistance
72.40.+w Photoconduction and photovoltaic effects
81.16.-c Methods of micro- and nanofabrication and processing
85.30.Tv Field effect devices

Energy dependent saturation width of swift heavy ion shaped embedded Au nanoparticles

P. Kluth, R. Giulian, D. J. Sprouster, C. S. Schnohr, A. P. Byrne, D. J. Cookson, and M. C. Ridgway

Appl. Phys. Lett. 94, 113107 (2009); http://dx.doi.org/10.1063/1.3099971 (3 pages) | Cited 10 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The transformation of Au nanoparticles (NPs) embedded in SiO2 from spherical to rod-like shapes induced by swift heavy ion irradiation has been studied. Irradiation was performed with 197Au ions at energies between 54 and 185 MeV. Transmission electron microscopy and small angle x-ray scattering measurements reveal an energy dependent saturation width of the NP rods as well as a minimum size required for the NPs to elongate. The NP saturation width is correlated with the ion track diameter in the SiO2. NP melting and in-plane strain in the irradiated SiO2 are discussed as potential mechanisms for the observed deformation.
Show PACS
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
61.82.Rx Nanocrystalline materials
64.70.Nd Structural transitions in nanoscale materials
62.25.-g Mechanical properties of nanoscale systems
78.70.Ck X-ray scattering
61.80.Jh Ion radiation effects

GaN quantum dots as optical transducers for chemical sensors

O. Weidemann, P. K. Kandaswamy, E. Monroy, G. Jegert, M. Stutzmann, and M. Eickhoff

Appl. Phys. Lett. 94, 113108 (2009); http://dx.doi.org/10.1063/1.3100301 (3 pages) | Cited 6 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
GaN/AlN quantum dots were investigated as optical transducers for field effect chemical sensors. The structures were synthesized by molecular-beam epitaxy and covered by a semitransparent catalytic Pt top contact. Due to the thin (3 nm) AlN barriers, the variation of the quantum dot photoluminescence with an external electric field along the [0001] axis is dominated by the tunneling current rather than by the quantum confined Stark effect. An increasing field results in a blueshift of the luminescence and a decreasing intensity. This effect is used to measure the optical response of quantum dot superlattices upon exposure to molecular hydrogen.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
07.07.Mp Transducers
73.40.Ns Metal-nonmetal contacts
73.40.Gk Tunneling
68.65.Hb Quantum dots (patterned in quantum wells)

Large tunability of Néel temperature by growth-rate-induced cation inversion in Mn-ferrite nanoparticles

Aria Yang, C. N. Chinnasamy, J. M. Greneche, Yajie Chen, Soack D. Yoon, Kailin Hsu, C. Vittoria, and V. G. Harris

Appl. Phys. Lett. 94, 113109 (2009); http://dx.doi.org/10.1063/1.3099340 (3 pages) | Cited 3 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The tuning of Néel temperature by greater than 100 K in nanoparticle Mn-ferrite was demonstrated by a growth-rate-induced cation inversion. Mn-ferrite nanoparticles, having diameters from 4 to 50 nm, were synthesized via coprecipitation synthesis. The Néel temperature (TN) increased inversely to the cation inversion parameter, δ (i.e., defined as (Mn1−δFeδ)tet[MnδFe2−δ]octO4). Concomitantly, TN increased with increased particle growth rate and particle size. These results unambiguously establish cation inversion as the dominant mechanism in modifying the superexchange leading to enhanced TN. The ability to tailor TN enables greater flexibility in applying nanoparticle ferrites in emerging technologies.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Tt Fine-particle systems; nanocrystalline materials
72.20.Pa Thermoelectric and thermomagnetic effects
81.16.-c Methods of micro- and nanofabrication and processing
75.30.Et Exchange and superexchange interactions
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
73.63.Bd Nanocrystalline materials

Metamaterial nanotips

C. Rockstuhl, C. R. Simovski, S. A. Tretyakov, and F. Lederer

Appl. Phys. Lett. 94, 113110 (2009); http://dx.doi.org/10.1063/1.3103208 (3 pages) | Cited 8 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanostructured metamaterials, especially arrays of metallic nanoparticles, which sustain the excitation of localized plasmon polaritons, provide excellent opportunities to mold the flow of light in the linear regime. We suggest a metamaterial structure whose properties are determined not only by its inner geometry but also by its entire shape. We call this structure a metamaterial nanotip. We evaluate the potential of this nanotip to control the size and the location of the field enhancement. Two-dimensional implementations of this metamaterial nanotip were comprehensively numerically simulated and confirm the expected, physically distinct regimes of operation.
Show PACS
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
42.70.-a Optical materials
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Slow light in quantum dot photonic crystal waveguides

Torben Roland Nielsen, Andrei Lavrinenko, and Jesper Mørk

Appl. Phys. Lett. 94, 113111 (2009); http://dx.doi.org/10.1063/1.3103286 (3 pages) | Cited 8 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A theoretical analysis of pulse propagation in a semiconductor quantum dot photonic crystal waveguide in the regime of electromagnetically induced transparency is presented. The slow light mechanism considered here is based on both material and waveguide dispersion. The group index ng for the combined system is significantly enhanced relative to slow light based on purely material or waveguide dispersion.
Show PACS
42.79.Gn Optical waveguides and couplers
42.55.Tv Photonic crystal lasers and coherent effects

Analysis of a SeCl4-graphite intercalate surface by thermovoltage scanning tunneling microscopy

J. Seifritz, Th. Wagner, B. Weyers, and R. Möller

Appl. Phys. Lett. 94, 113112 (2009); http://dx.doi.org/10.1063/1.3095662 (3 pages) | Cited 1 time

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The local thermoelectric properties of a SeCl4-graphite intercalate compound (SeCl4-GIC) are studied by means of scanning-tunneling microscopy (STM). The analysis by micro-Raman spectroscopy suggested two domains, a “carbonlike” and a “SeCl4-GIC-like.” By using the thermovoltage that arises if a temperature difference between the tunneling tip and the sample of a STM is applied, areas with a difference in the local density of states can be distinguished with high lateral resolution. The differences in the local thermopower may be as large as several hundred μV/K. The aim was to estimate the contribution of the different domains to the thermopower of SeCl4-GIC.
Show PACS
72.20.Pa Thermoelectric and thermomagnetic effects
72.80.Rj Fullerenes and related materials
78.30.Na Fullerenes and related materials
78.30.Hv Other nonmetallic inorganics
71.20.Tx Fullerenes and related materials; intercalation compounds
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)

Impacts of size and cross-sectional shape on surface lattice constant and electron effective mass of silicon nanowires

Donglai Yao, Gang Zhang, Guo-Qiang Lo, and Baowen Li

Appl. Phys. Lett. 94, 113113 (2009); http://dx.doi.org/10.1063/1.3103366 (3 pages) | Cited 10 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the surface lattice and electronic structure of [110] oriented hydrogen-passivated silicon nanowires (SiNWs) of different cross-sectional shapes by using the first-principles tight-binding method. Remarkable quantum confinement effects are observed on the surface lattice constant and the electron effective mass. Moreover, with the same cross-sectional area, the triangular-SiNW has more obvious size dependence than rectangular-SiNW. The significant size and cross-sectional shape effects are explained by the concept of surface-to-volume ratio. Our results demonstrate that due to the smaller electron effective mass, the rectangular-SiNW has obvious advantage over triangular-SiNW in application in higher on current in SiNW transistor.
Show PACS
73.22.-f Electronic structure of nanoscale materials and related systems
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
71.20.Mq Elemental semiconductors
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)
81.65.Rv Passivation

Direct to indirect band gap transition in ultrathin ZnO nanowires under uniaxial compression

Yang Zhang, Yu-Hua Wen, Jin-Cheng Zheng, and Zi-Zhong Zhu

Appl. Phys. Lett. 94, 113114 (2009); http://dx.doi.org/10.1063/1.3104852 (3 pages) | Cited 17 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The direct to indirect band gap transition in ultrathin [0001] ZnO nanowires with the structural transformation from the regular wurtzite structure to a more close-packed hexagonal structure during uniaxial compression is studied by using the first-principles calculations. The results show that all ZnO nanowires exhibit direct band gap in wurtzite structure and indirect band gap in hexagonal structure. For the same wire the band gap in hexagonal structure is smaller than that in wurtzite structure. The origin of the band gap transition from direct to indirect one is discussed.
Show PACS
73.21.Hb Quantum wires
71.15.-m Methods of electronic structure calculations
64.70.K- Solid-solid transitions
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
back to top
RSS Feeds
FREE

Light-induced charge transfer in hybrid composites of organic semiconductors and silicon nanocrystals

Roland Dietmueller, Andre R. Stegner, Robert Lechner, Sabrina Niesar, Rui N. Pereira, Martin S. Brandt, André Ebbers, Martin Trocha, Hartmut Wiggers, and Martin Stutzmann

Appl. Phys. Lett. 94, 113301 (2009); http://dx.doi.org/10.1063/1.3086299 (3 pages) | Cited 14 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Charge transfer between silicon nanocrystals (Si-nc) and organic semiconductors has been investigated via light-induced electron spin resonance (LESR). Composites of Si-nc with the hole conductor poly(3-hexylthiophene) (P3HT) and with the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) have been investigated. The LESR measurements allow one to quantify light-induced charge transfer between Si-nc and P3HT, which results in positive P3HT polarons. PCBM, in contrast, acts as an electron acceptor in composites with Si-nc, and after illumination, negative PCBM radicals are created. These results are discussed in terms of light-induced generation and separation of charge carriers in the hybrid composites.
Show PACS
73.63.Bd Nanocrystalline materials
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.40.+w Photoconduction and photovoltaic effects
71.38.-k Polarons and electron-phonon interactions
76.30.Pk Conduction electrons
FREE

Transient photovoltaic behavior of air-stable, inverted organic solar cells with solution-processed electron transport layer

Chang Su Kim, Stephanie S. Lee, Enrique D. Gomez, Jong Bok Kim, and Yueh-Lin Loo

Appl. Phys. Lett. 94, 113302 (2009); http://dx.doi.org/10.1063/1.3099947 (3 pages) | Cited 41 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The short-circuit current density of inverted organic solar cells comprising a solution-processed titania electron transport layer increases with continuous illumination in air and saturates after 10 min. On extended exposure (>2 days), the open-circuit voltage of the devices increases also. The improvement in device characteristics over short time scales is attributed to the filling of shallow electron traps in titania. With an increase in photoconductivity of titania, the short-circuit current increases accordingly. The increase in open-circuit voltage on extended exposure to air is attributed to an increase in the electrostatic field across the diodes when polythiophene is doped by oxygen.
Show PACS
84.60.Jt Photoelectric conversion
61.72.up Other materials
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
FREE

Low-voltage organic transistors with titanium oxide/polystyrene bilayer dielectrics

Yingxi Lu, Wi Hyoung Lee, Hwa Sung Lee, Yunseok Jang, and Kilwon Cho

Appl. Phys. Lett. 94, 113303 (2009); http://dx.doi.org/10.1063/1.3097010 (3 pages) | Cited 14 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Pentacene-based low-voltage organic transistors were realized with titanium oxide/polystyrene (TiO2/PS) bilayer dielectrics. Significantly, the TiO2 bottom layer was fabricated by a layer-by-layer deposition procedure and had an ultrathin thickness (<5 nm). The nonpolar PS top layer not only shields out the high polarity TiO2 layer, but also reduces the roughness of the dielectric, which results in low gate leakage of dielectric and the more ordered growth of pentacene film. This organic transistor with a TiO2/PS bilayer dielectric was found to exhibit high performance with a low operating voltage ( ≤ 3 V), and a high on/off ratio (>107).
Show PACS
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
85.30.Tv Field effect devices
77.55.-g Dielectric thin films
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
Page 3 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close