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

23 Apr 2012

Volume 100, Issue 17, Articles (17xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 171903 (2012); http://dx.doi.org/10.1063/1.4704193 (3 pages)

Y. Peng and K. Kempa
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Nanotube-based scanning rotational microscope

Andrey M. Popov, Irina V. Lebedeva, and Andrey A. Knizhnik

Appl. Phys. Lett. 100, 173101 (2012); http://dx.doi.org/10.1063/1.4705430 (4 pages) | Cited 1 time

Online Publication Date: 23 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A scheme of the scanning rotational microscope is designed. This scheme is based on using carbon nanotubes simultaneously as a probe tip and as a bolt/nut pair which converts translational displacements of two piezo actuators into pure rotation of the probe tip. First-principles calculations of the interaction energy between movable and rotational parts of the microscope confirm the capability for its operation. The scanning rotational microscope with a chemically functionalized nanotube-based tip can be used to study how the interaction between individual molecules or a molecule and a surface depends on their relative orientation.
Show PACS
07.79.-v Scanning probe microscopes and components
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Strain relaxation by dislocation glide in ZnO/ZnMgO core-shell nanowires

G. Perillat-Merceroz, R. Thierry, P.-H. Jouneau, P. Ferret, and G. Feuillet

Appl. Phys. Lett. 100, 173102 (2012); http://dx.doi.org/10.1063/1.4704927 (4 pages) | Cited 3 times

Online Publication Date: 23 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Plastic relaxation of the misfit stress in core-shell semi-conducting nanowires can lead to structural defects, detrimental to applications. Core-shell Zn0.7Mg0.3O/ZnO quantum well heterostructures were deposited on ZnO nanowires. Strain along the a and c axes of the wurtzite structure is relaxed through the glide of dislocation half-loops from the free surfaces, within pyramidal and prismatic planes. Some half-loops are closed up in the barriers to accommodate the misfit at two consecutive interfaces of the quantum well stack. Dislocations are also observed within the nanowire core: contrary to two-dimensional structures, both the core and the shell can be plastically relaxed.
Show PACS
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
68.65.La Quantum wires (patterned in quantum wells)
81.40.Lm Deformation, plasticity, and creep
62.20.fq Plasticity and superplasticity
68.65.Fg Quantum wells

Enhancement of Raman scattering by field superposition of rough submicrometer silver particles

Feng Zhang, Ping Chen, Lei Zhang, Song-Cheng Mao, Lie Lin, Yu-Guo Tang, Ji-Cheng Cui, Xiang-Dong Qi, Jun-Hong Yang, and Yun-Feng Ma

Appl. Phys. Lett. 100, 173103 (2012); http://dx.doi.org/10.1063/1.4705083 (4 pages) | Cited 2 times

Online Publication Date: 23 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Wavelength-dependent surface-enhanced Raman spectra of methylene blue adsorbed on rough submicrometer silver particles were measured. Results revealed a high enhancement factor (105 ∼ 107), especially in the long-wavelength region. Investigation on the far- and near-field optical properties of the particles showed a remarkably enhanced dipole plasmon resonance due to the presence of a rough particle surface. Through analyzing the plasmon resonance modes and the superposition of radiation fields, we found that the rough surface-induced field superposition results in the redistribution of optical fields around the particle, which becomes a key factor responsible for the high enhancement effect of metal particles.
Show PACS
78.30.Er Solid metals and alloys
68.43.Mn Adsorption kinetics
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
68.35.bd Metals and alloys

Impacts of image force on the Schottky barrier height at metal-carbon nanotube contacts

Gang Zhang and Qing Shi

Appl. Phys. Lett. 100, 173104 (2012); http://dx.doi.org/10.1063/1.4705300 (3 pages) | Cited 2 times

Online Publication Date: 23 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By using first-principles calculations and classical image force model, we studied the image force induced Schottky barrier (SB) height reduction in carbon nanotube (CNT)-metal contact. A low dielectric constant leads to a stronger band bending and therefore strongly reduces the SB height. This reduction depends on carrier concentration and CNT diameter. For CNT with carrier concentration of 1020 cm−3, the reduction in SB height caused by image force is up to 0.7 eV when CNT diameter is less than 20 Å. Our results demonstrate that image force induced SB height reduction is important for the design of CNT-based nanoelectronic devices.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.30.+y Surface double layers, Schottky barriers, and work functions
77.22.Ch Permittivity (dielectric function)

Apparent Raman spectral shifts from nano-structured surfaces

V. Tishkova and W. S. Bacsa

Appl. Phys. Lett. 100, 173105 (2012); http://dx.doi.org/10.1063/1.4704928 (4 pages)

Online Publication Date: 24 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We observe Raman spectral shifts when scanning the focal spot over trenches in gallium arsenide. The Raman spectral shifts induced by topography are only present when the trenches are parallel to the spectrometer grating grooves. The topography induced spectral shifts are explained by spatial modification of the emitted beam due to surface topography leading to a non uniform illumination of the focal spot. The non uniform illumination of the focal spot influences the grating angle leading to the observed spectral shift. Apparent Raman spectral shifts of nano-structured surfaces can be reduced when under focusing at the expense of recording lower signals or using objectives with a low numerical aperture. This shows that topography induced spectral shifts need to be taken into account when recording optical spectra from nano-structured surfaces.
Show PACS
78.30.Fs III-V and II-VI semiconductors
78.40.Fy Semiconductors
61.46.Hk Nanocrystals
68.35.bg Semiconductors

Using carbon chains to mediate magnetic coupling in zigzag graphene nanoribbons

Min Kan, Jian Zhou, Yawei Li, and Qiang Sun

Appl. Phys. Lett. 100, 173106 (2012); http://dx.doi.org/10.1063/1.4705302 (4 pages) | Cited 2 times

Online Publication Date: 24 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Graphene nanoribbon and atomic carbon chain are allotropes of carbon, attracting tremendous attention from multidisciplinary areas ranging from nano physics to astrophysics. Here, first-principles calculations based on density-functional theory are carried out to study the ferromagnetic coupling in zigzag-edged graphene nanoribbons linked by carbon chains. Compared to the existing methods for ferromagnetic graphene nanoribbons, carbon chain linkage is found to be more effective for larger magnetic exchange energy and also be more flexible in tuning the electronic structure and magnetism.
Show PACS
73.22.Pr Electronic structure of graphene
81.05.ue Graphene
75.75.Cd Fabrication of magnetic nanostructures
75.75.Lf Electronic structure of magnetic nanoparticles
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
72.80.Vp Electronic transport in graphene

Lithium-ion conducting La2/3−xLi3xTiO3 solid electrolyte thin films with stepped and terraced surfaces

Hiromichi Ohta, Teruyasu Mizoguchi, Noriyuki Aoki, Takashi Yamamoto, Akhmad Sabarudin, and Tomonari Umemura

Appl. Phys. Lett. 100, 173107 (2012); http://dx.doi.org/10.1063/1.4709402 (4 pages) | Cited 4 times

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF


See Also: RETRACTION

Show Abstract
La2/3−xLi3xTiO3 (LLT, x = 0.1 and 0.167) thin films were grown on (001)-oriented SrTiO3 (STO) substrates by pulsed laser deposition. The resultant LLT films were heteroepitaxially grown with atomically flat surfaces. Although the films considered to be single crystalline, they were composed of 90°-rotated multi domains (∼5 nm in size) with epitaxial relationships of (100) [001] LLT || (001) [100] STO and (100) [010] LLT || (001) [100] STO. The bulk conductivity of the LLT (x = 0.1) films was 2.5 × 10−2 S cm−1 at 190 °C, comparable to that of a bulk single crystalline LLT. Single crystalline LLT thin films with atomically flat surfaces should help clarify interfacial lithium-ion conductivity.
Show PACS
66.30.hp Molecular crystals
68.60.-p Physical properties of thin films, nonelectronic
68.55.ag Semiconductors
82.47.Aa Lithium-ion batteries
82.45.Gj Electrolytes

Assessment of the resonance frequency of cantilever carbon nanocones using molecular dynamics simulation

R. D. Firouz-Abadi, H. Amini, and A. R. Hosseinian

Appl. Phys. Lett. 100, 173108 (2012); http://dx.doi.org/10.1063/1.4705423 (4 pages)

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The resonance frequencies of cantilever carbon nanocones (CNCs) up to 4 nm in height are determined using molecular dynamics simulation based on adaptive intermolecular reactive empirical bond order potential. The frequency content of the free vibrations of CNCs under a lateral initial excitation at the tip is analyzed using fast Fourier transformation, and the resonance frequencies are obtained. The results are reported for various samples to investigate the dependency of the resonance frequency to the geometrical parameters and temperature of CNCs.
Show PACS
02.70.Ns Molecular dynamics and particle methods
02.60.-x Numerical approximation and analysis
02.30.Uu Integral transforms
61.46.-w Structure of nanoscale materials

Planar PbS quantum dot/C60 heterojunction photovoltaic devices with 5.2% power conversion efficiency

E. J. D. Klem, C. W. Gregory, G. B. Cunningham, S. Hall, D. S. Temple, and J. S. Lewis

Appl. Phys. Lett. 100, 173109 (2012); http://dx.doi.org/10.1063/1.4707377 (4 pages) | Cited 3 times

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Of interest for both photovoltaic and photodetector applications is the ability of colloidal quantum dot (CQD) devices to provide response further into the infrared than is typical for other solution-processable materials. Here, we present a simple heterojunction diode structure that utilizes the extended infrared absorption of PbS CQDs. We show that device performance benefits from a discontinuous exciton blocking layer which improves charge separation without limiting charge extraction. By enhancing charge carrier mobility in the CQD layer, we demonstrate a planar heterostructure device with a power conversion efficiency of 5.2% under 1 sun illumination.
Show PACS
85.60.Bt Optoelectronic device characterization, design, and modeling
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
85.65.+h Molecular electronic devices
78.67.Hc Quantum dots

Low-power, fast, selective nanoparticle-based hydrogen sulfide gas sensor

William Mickelson, Allen Sussman, and Alex Zettl

Appl. Phys. Lett. 100, 173110 (2012); http://dx.doi.org/10.1063/1.3703761 (4 pages) | Cited 3 times

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a small, low-cost, low-power, highly sensitive, and selective nanomaterials-based gas sensor. A network of tungsten oxide nanoparticles is heated by an on-chip microhotplate while the conductance of the network is monitored. The device can be heated with short pulses, thereby drastically lowering the power consumption, without diminishing the sensor response. The sensor shows high sensitivity to hydrogen sulfide and does not have significant cross sensitivities to hydrogen, water, or methane, gases likely to be present in operation. A sensing mechanism is proposed, and its effect on electronic properties is discussed.
Show PACS
82.80.-d Chemical analysis and related physical methods of analysis
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
73.22.-f Electronic structure of nanoscale materials and related systems

Dissipation mechanisms in thermomechanically driven silicon nitride nanostrings

A. Suhel, B. D. Hauer, T. S. Biswas, K. S. D. Beach, and J. P. Davis

Appl. Phys. Lett. 100, 173111 (2012); http://dx.doi.org/10.1063/1.4704914 (5 pages) | Cited 3 times

Online Publication Date: 25 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-stress silicon nitride nanostrings are a promising system for sensing applications because of their ultra-high mechanical quality factors (Qs). By performing thermomechanical calibration across multiple vibrational modes, we are able to assess the roles of the various dissipation mechanisms in these devices. Specifically, we possess a set of nanostrings in which all measured modes fall upon a single curve of peak displacement versus frequency. This allows us to rule out bulk bending and intrinsic loss mechanisms as dominant sources of dissipation and to conclude that the most significant contribution to dissipation in high-stress nanostrings occurs at the anchor points.
Show PACS
07.10.Cm Micromechanical devices and systems

Metal-insulator transition with multiple micro-scaled avalanches in VO2 thin film on TiO2(001) substrates

Kenichi Kawatani, Hidefumi Takami, Teruo Kanki, and Hidekazu Tanaka

Appl. Phys. Lett. 100, 173112 (2012); http://dx.doi.org/10.1063/1.4709429 (3 pages) | Cited 3 times

Online Publication Date: 26 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We observed micro-scale phase separation in VO2 thin films on TiO2(001) substrates and investigated the relationship between the appearance of metallic domains and the abrupt resistive changes around the phase transition. The resistive changes are interpreted using a combined resistance model of the two phases, and the conductance evaluated from the visualized domain behavior was consistent with the electronic properties. These results indicate the importance of modifying conductive behavior spatially using a partial phase transition.
Show PACS
71.30.+h Metal-insulator transitions and other electronic transitions
68.55.-a Thin film structure and morphology

Substrate-assisted nucleation of ultra-thin dielectric layers on graphene by atomic layer deposition

B. Dlubak, P. R. Kidambi, R. S. Weatherup, S. Hofmann, and J. Robertson

Appl. Phys. Lett. 100, 173113 (2012); http://dx.doi.org/10.1063/1.4707376 (4 pages) | Cited 2 times

Online Publication Date: 26 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on a large improvement in the wetting of Al2O3 thin films grown by un-seeded atomic layer deposition on monolayer graphene, without creating point defects. This enhanced wetting is achieved by greatly increasing the nucleation density through the use of polar traps induced on the graphene surface by an underlying metallic substrate. The resulting Al2O3/graphene stack is then transferred to SiO2 by standard methods.
Show PACS
68.55.A- Nucleation and growth
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
64.60.Q- Nucleation
77.55.-g Dielectric thin films
77.84.-s Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials

Gold nanoring as a sensitive plasmonic biosensor for on-chip DNA detection

Chengjun Huang (黄成军), Jian Ye (叶坚), Shuo Wang (王硕), Tim Stakenborg, and Liesbet Lagae

Appl. Phys. Lett. 100, 173114 (2012); http://dx.doi.org/10.1063/1.4707382 (4 pages) | Cited 7 times

Online Publication Date: 26 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report an on-chip nanosensor based on the localized surface plasmon resonance (LSPR) property of gold nanorings. The fabricated nanorings using nanosphere lithography showed highly tunable optical properties and were optimized to boost LSPR-based biosensing. The LSPR extinction spectra of the nanosensor agreed well with the theoretical calculations using a finite-difference time-domain model. Such an on-chip nanoring-based biosensor showed a refractive index sensitivity of 350 nm/refractive index unit with a figure of merit of 3.1 and was utilized to detect DNA in a real-time and label-free manner.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
02.70.Bf Finite-difference methods
87.85.Rs Nanotechnologies-applications
87.15.-v Biomolecules: structure and physical properties

Interaction of a bi-molecular liquid crystal film with functionalized nanoparticles

Jefferson W. Taylor, Lynn K. Kurihara, and L. J. Martínez-Miranda

Appl. Phys. Lett. 100, 173115 (2012); http://dx.doi.org/10.1063/1.3703605 (3 pages) | Cited 3 times

Online Publication Date: 26 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the properties of a bi-molecular film of liquid crystal close to a magnetic nanoparticle terminated with a variety of functionalization compounds using atomic force microscopy. Studies in bulk liquid crystals have shown that the functionalization compound influences how the liquid crystal reorients. The results of this investigation are compared to the results of work done on phospholipids in close contact with uncovered silica nanoparticles. Our studies of the liquid crystal in contact with the nanoparticles show that its behavior is dependent on the functionalization compound.
Show PACS
68.15.+e Liquid thin films
75.75.-c Magnetic properties of nanostructures
75.50.Tt Fine-particle systems; nanocrystalline materials
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order

High-Q silicon optomechanical microdisk resonators at gigahertz frequencies

Xiankai Sun, Xufeng Zhang, and Hong X. Tang

Appl. Phys. Lett. 100, 173116 (2012); http://dx.doi.org/10.1063/1.4709416 (4 pages) | Cited 7 times

Online Publication Date: 27 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report disk-shaped silicon optomechanical resonators with frequency up to 1.75 GHz in the ultrahigh frequency band. Optical transduction of the thermal motion of the disks’ in-plane vibrational modes yields a displacement sensitivity of 4.1 × 10−17 m/Hz1/2. Due to the reduced clamping loss, these disk resonators possess high mechanical quality factors (Q), with the highest value of 4370 for the 1.47 GHz mode measured in ambient air. Numerical simulation on the modal frequency and mechanical Q for disks of varying undercut shows modal coupling and suggests a realistic pedestal size to achieve the highest possible Q.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
84.40.Az Waveguides, transmission lines, striplines
07.10.Cm Micromechanical devices and systems
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close