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

2 Apr 2012

Volume 100, Issue 14, Articles (14xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 144101 (2012); http://dx.doi.org/10.1063/1.3697983 (4 pages)

H. Xu (徐涵), Wei Yu (余玮), M. Y. Yu (郁明阳), A. Y. Wong (黄燿煇), Z. M. Sheng (盛政明), M. Murakami (村上匡且), and J. Zhang (张杰)
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Raman sensitivity to crystal structure in InAs nanowires

Jaya Kumar Panda, Anushree Roy, Achintya Singha, Mauro Gemmi, Daniele Ercolani, Vittorio Pellegrini, and Lucia Sorba

Appl. Phys. Lett. 100, 143101 (2012); http://dx.doi.org/10.1063/1.3698115 (3 pages) | Cited 3 times

Online Publication Date: 2 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report electron transmission and Raman spectroscopy study of InAs nanowires. We demonstrate that the temperature dependent behavior of optical phonon energies can be used to determine the relative wurtzite fraction in the InAs nanowires. Furthermore, we propose that the interfacial strain between zincblende and wurtzite phases along the length of the wires manifests in the temperature-evolution of the phonon linewidths. From these studies, temperature-dependent Raman measurements emerge as a non-invasive method to study polytypism in such nanowires.
Show PACS
78.30.Fs III-V and II-VI semiconductors
61.46.Km Structure of nanowires and nanorods (long, free or loosely attached, quantum wires and quantum rods, but not gate-isolated embedded quantum wires)
63.22.Gh Nanotubes and nanowires
78.67.Uh Nanowires
81.07.Gf Nanowires

Operation of multi-finger graphene quantum capacitance varactors using planarized local bottom gate electrodes

M. A. Ebrish, H. Shao, and S. J. Koester

Appl. Phys. Lett. 100, 143102 (2012); http://dx.doi.org/10.1063/1.3698394 (4 pages) | Cited 1 time

Online Publication Date: 2 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The operation of multi-finger graphene quantum capacitance varactors fabricated using a planarized local bottom gate electrode, HfO2 gate dielectric, and large-area graphene is described. As a function of the gate bias, the devices show a room-temperature capacitance tuning range of 1.22–1 over a voltage range of ±2 V. An excellent theoretical fit of the temperature-dependent capacitance-voltage characteristics is obtained when random potential fluctuations with standard deviation of 65 mV are included. The results represent a first step in realizing graphene quantum capacitance varactors for wireless sensing applications.
Show PACS
84.32.Tt Capacitors

Readout of carbon nanotube vibrations based on spin-phonon coupling

C. Ohm, C. Stampfer, J. Splettstoesser, and M. R. Wegewijs

Appl. Phys. Lett. 100, 143103 (2012); http://dx.doi.org/10.1063/1.3698395 (4 pages) | Cited 6 times

Online Publication Date: 2 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a scheme for spin-based detection of the bending motion in suspended carbon-nanotubes, using the curvature-induced spin-orbit interaction. We show that the resulting effective spin-phonon coupling can be used to down-convert the high-frequency vibration-modulated spin-orbit field to spin-flip processes at a much lower frequency. This vibration-induced spin-resonance can be controlled with an axial magnetic field. We propose a Pauli spin blockade readout scheme and predict that the leakage current shows pronounced peaks as a function of the external magnetic field. Whereas the resonant peaks allow for frequency readout, the slightly off-resonant current is sensitive to the vibration amplitude.
Show PACS
62.25.Jk Mechanical modes of vibration
63.20.K- Phonon interactions
61.46.Fg Nanotubes
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect

Quantized charge pumping through a carbon nanotube double quantum dot

S. J. Chorley, J. Frake, C. G. Smith, G. A. C. Jones, and M. R. Buitelaar

Appl. Phys. Lett. 100, 143104 (2012); http://dx.doi.org/10.1063/1.3700967 (3 pages) | Cited 3 times

Online Publication Date: 3 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate single-electron pumping in a gate-defined carbon nanotube double quantum dot. By periodic modulation of the potentials of the two quantum dots, we move the system around charge triple points and transport exactly one electron or hole per cycle. We investigate the pumping as a function of the modulation frequency and amplitude and observe good current quantization up to frequencies of 18 MHz where rectification effects cause the mechanism to break down.
Show PACS
73.63.Fg Nanotubes
73.63.Hs Quantum wells
73.40.Ei Rectification

Temperature dependence of dynamic nuclear polarization and its effect on electron spin relaxation and dephasing in InAs/GaAs quantum dots

J. Beyer, Y. Puttisong, I. A. Buyanova, S. Suraprapapich, C. W. Tu, and W. M. Chen

Appl. Phys. Lett. 100, 143105 (2012); http://dx.doi.org/10.1063/1.3701273 (4 pages) | Cited 1 time

Online Publication Date: 3 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electron spin dephasing and relaxation due to hyperfine interaction with nuclear spins is studied in an InAs/GaAs quantum dot ensemble as a function of temperature up to 85 K, in an applied longitudinal magnetic field. The extent of hyperfine-induced dephasing is found to decrease, whereas dynamic nuclear polarization increases with increasing temperature. We attribute both effects to an accelerating electron spin relaxation through phonon-assisted electron-nuclear spin flip-flops driven by hyperfine interactions, which could become the dominating contribution to electron spin depolarization at high temperatures.
Show PACS
72.25.-b Spin polarized transport
71.70.Jp Nuclear states and interactions
73.21.La Quantum dots
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Freestanding nanostructures for three-dimensional superconducting nanodevices

Ajuan Cui, Wuxia Li, Qiang Luo, Zhe Liu, and Changzhi Gu

Appl. Phys. Lett. 100, 143106 (2012); http://dx.doi.org/10.1063/1.3701283 (4 pages) | Cited 1 time

Online Publication Date: 4 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Free-space nanostructures are the fundamental building blocks of three-dimensional (3D) nanodevices with multi-functionality beyond that achievable by planar devices. Here we developed a reliable technique for the site-specific post-growth geometrical manipulation of freestanding superconducting nanowires using ion-beam irradiation with nanometer-scale resolution to fabricate uniformly shaped and sized clean-surface 3D nanostructures. Such structures could integrate with conventional superconducting quantum interference devices to detect magnetic fields both parallel and normal to the substrate. Property characterizations suggest that our focused-ion-beam technique allows tailoring of freestanding superconducting loops for size and geometry, potentially for lab-on-chip experiments.
Show PACS
81.07.Gf Nanowires
61.80.Jh Ion radiation effects
68.65.La Quantum wires (patterned in quantum wells)
81.16.-c Methods of micro- and nanofabrication and processing
85.25.Dq Superconducting quantum interference devices (SQUIDs)

Automated markerless full field hard x-ray microscopic tomography at sub-50 nm 3-dimension spatial resolution

Jun Wang, Yu-chen Karen Chen, Qingxi Yuan, Andrei Tkachuk, Can Erdonmez, Benjamin Hornberger, and Michael Feser

Appl. Phys. Lett. 100, 143107 (2012); http://dx.doi.org/10.1063/1.3701579 (4 pages) | Cited 11 times

Online Publication Date: 4 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A full field transmission x-ray microscope (TXM) has been developed and commissioned at the National Synchrotron Light Source at Brookhaven National Laboratory. The capabilities we developed in auto-tomography, local tomography, and spectroscopic imaging that overcome many of the limitations and difficulties in existing transmission x-ray microscopes are described and experimentally demonstrated. Sub-50 nm resolution in 3-dimension (3D) with markerless automated tomography has been achieved. These capabilities open up scientific opportunities in many research fields.
Show PACS
68.37.Yz X-ray microscopy
07.85.Nc X-ray and γ-ray spectrometers
07.85.Tt X-ray microscopes

Proposal for tunnel-field-effect-transistor as ultra-sensitive and label-free biosensors

Deblina Sarkar and Kaustav Banerjee

Appl. Phys. Lett. 100, 143108 (2012); http://dx.doi.org/10.1063/1.3698093 (4 pages) | Cited 4 times

Online Publication Date: 5 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Tunnel field-effect-transistor (TFET) based biosensor is proposed, and it is shown that they can surpass by several orders, the performance of those based on conventional FET (CFET) and hence, can potentially revolutionize the biosensing applications. Analytical formula is derived for the sensitivity and response time to provide physical insights in terms of material bandgap and operation regime of the TFET biosensor for achieving optimal results. At the same time, rigorous numerical simulations have been performed in order to obtain accurate values of sensitivity for both biomolecule and pH sensing operations. The time dependent response of the biosensors has also been discussed through analytical and numerical solutions. It is shown that while the CFET biosensors suffer from fundamental limitations on the maximum sensitivity and minimum detection time achievable, TFET biosensors, with their fundamentally different current injection mechanism in the form of band-to-band tunneling, can overcome such limitations and lead to over four orders of magnitude higher sensitivity and over an order of magnitude lower response time.
Show PACS
82.47.Rs Electrochemical sensors
82.80.Fk Electrochemical methods
85.30.Tv Field effect devices
87.80.Kc Electrochemical techniques
02.60.-x Numerical approximation and analysis

Metallic nanomesh electrodes with controllable optical properties for organic solar cells

Jinfeng Zhu, Xiaodan Zhu, Ryan Hoekstra, Lu Li, Faxian Xiu, Mei Xue, Baoqing Zeng, and Kang L. Wang

Appl. Phys. Lett. 100, 143109 (2012); http://dx.doi.org/10.1063/1.3701582 (4 pages) | Cited 4 times

Online Publication Date: 6 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated a metallic nanomesh using nanosphere lithography and metal evaporation. The metallic nanomesh has a precisely controlled nanostructure showing excellent uniformity with hexagonally arrayed periodic circular holes. A P3HT:PCBM organic solar cell, with the gold nanomesh electrode, demonstrates a high fill factor of 61% and a considerable power conversion efficiency of 3.12%. Electromagnetic simulation indicates that the optical properties of the metallic nanomesh can be optimized for organic photovoltaic devices by tuning the film thickness, hole diameter, and periodicity. These results show the promising potential of using a metallic nanomesh as the transparent electrode in organic solar cells.
Show PACS
81.16.Nd Micro- and nanolithography
68.55.jd Thickness
88.40.hj Efficiency and performance of solar cells
88.40.jr Organic photovoltaics
61.46.-w Structure of nanoscale materials
81.07.Bc Nanocrystalline materials

Few electron double quantum dot in an isotopically purified 28Si quantum well

A. Wild, J. Kierig, J. Sailer, J. W. Ager, III, E. E. Haller, G. Abstreiter, S. Ludwig, and D. Bougeard

Appl. Phys. Lett. 100, 143110 (2012); http://dx.doi.org/10.1063/1.3701588 (4 pages) | Cited 4 times

Online Publication Date: 6 April 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a few electron double quantum dot device defined in an isotopically purified 28Si quantum well (QW). An electron mobility of 5.5·104cm2(Vs)-1 is observed in the QW, which is the highest mobility ever reported for a two-dimensional electron system in 28Si. The residual concentration of 29Si nuclei in the 28Si QW is lower than 103ppm, at the verge where the hyperfine interaction is theoretically no longer expected to dominantly limit the T2 spin dephasing time. We also demonstrate a complete suppression of hysteretic gate behavior and charge noise using a negatively biased global top gate.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Cw Elemental semiconductors
71.70.Jp Nuclear states and interactions
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close