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4 Jan 2010

Volume 96, Issue 1, Articles (01xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 96, 013107 (2010); http://dx.doi.org/10.1063/1.3280900 (3 pages)

L. Fernández, M. Corso, F. Schiller, M. Ilyn, M. Holder, and J. E. Ortega
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Editorial

Nghi Q. Lam

Appl. Phys. Lett. 96, 010401 (2010); http://dx.doi.org/10.1063/1.3292946 (1 page)

Online Publication Date: 7 January 2010

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Dual band terahertz waveguiding on a planar metal surface patterned with annular holes

C. R. Williams, M. Misra, S. R. Andrews, S. A. Maier, S. Carretero-Palacios, S. G. Rodrigo, F. J. Garcia-Vidal, and L. Martin-Moreno

Appl. Phys. Lett. 96, 011101 (2010); http://dx.doi.org/10.1063/1.3276545 (3 pages) | Cited 7 times

Online Publication Date: 4 January 2010

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We report studies of the guiding of terahertz radiation on a copper surface textured with an array of blind annular holes. The structure supports two tightly bound surface plasmon-polaritonlike electromagnetic waves associated with TE11 and TEM coaxial waveguide modes. The TE11-like surface mode has a cutoff determined by the array period while the TEM mode can be arranged to have a lower frequency cut-off by adjusting the hole depth. The ability to guide two modes in independently variable bands could be useful in quantitative chemical sensing.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
68.37.Lp Transmission electron microscopy (TEM)
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
78.70.Gq Microwave and radio-frequency interactions
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Low voltage and high transmittance blue-phase liquid crystal displays with corrugated electrodes

Meizi Jiao, Yan Li, and Shin-Tson Wu

Appl. Phys. Lett. 96, 011102 (2010); http://dx.doi.org/10.1063/1.3290253 (3 pages) | Cited 35 times

Online Publication Date: 4 January 2010

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A low voltage (<10 V) and high transmittance ( ∼ 85.6%) polymer-stabilized blue-phase liquid crystal (BPLC) display is proposed. The periodic corrugated electrodes generate a strong horizontal field component to induce isotropic-to-anisotropic transition in the BPLC medium through Kerr effect. Moreover, this field is uniformly distributed across the entire LC layer so that the accumulated phase retardation along the beam path is large, resulting in low voltage and high transmittance. This approach enables BPLC to be addressed by amorphous-silicon thin film transistors, which would accelerate its emergence as next-wave display technology.
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85.60.Pg Display systems
85.30.Tv Field effect devices

Monte Carlo study of carrier-light coupling in terahertz quantum cascade lasers

Christian Jirauschek

Appl. Phys. Lett. 96, 011103 (2010); http://dx.doi.org/10.1063/1.3284523 (3 pages) | Cited 14 times

Online Publication Date: 4 January 2010

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We present a method for self-consistently including the optical cavity field into Monte Carlo-based carrier transport simulations. This approach allows for an analysis of the actual lasing operation in quantum cascade lasers, considering effects such as gain, saturation, and longitudinal mode competition. Simulation results for a terahertz quantum cascade laser are found to be consistent with experiment.
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42.55.Px Semiconductor lasers; laser diodes
02.70.Uu Applications of Monte Carlo methods
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems

Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

G. Fiol, D. Arsenijević, D. Bimberg, A. G. Vladimirov, M. Wolfrum, E. A. Viktorov, and Paul Mandel

Appl. Phys. Lett. 96, 011104 (2010); http://dx.doi.org/10.1063/1.3279136 (3 pages) | Cited 10 times

Online Publication Date: 5 January 2010

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Hybrid mode-locking in monolithic quantum dot (QD) lasers is studied experimentally and theoretically. A strong asymmetry of the locking range with respect to the passive mode locking frequency is observed. The width of this range increases linearly with the modulation amplitude for all operating parameters. Maximum locking range found is 30 MHz. The results of a numerical analysis performed using a set of delay-differential equations taking into account carrier exchange between QDs and wetting layer are in agreement with experiments and indicate that a spectral filtering element could improve locking characteristics.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.79.Ci Filters, zone plates, and polarizers
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Epitaxial growth of one-dimensional GaN nanostructures with enhanced near-band edge emission by chemical vapor deposition

Taeseup Song, Won Il Park, and Ungyu Paik

Appl. Phys. Lett. 96, 011105 (2010); http://dx.doi.org/10.1063/1.3279147 (3 pages) | Cited 1 time

Online Publication Date: 5 January 2010

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We report a simple chemical vapor deposition method for epitaxial growth of hierarchical GaN one-dimensional nanostructures (1DNSs) that have good optical characteristics. By changing the evaporation temperature of the Ga source, we were able to change the morphologies of GaN 1DNSs from hexagonal-faceted, pencil-like structures to rough-surfaced, polygonal towerlike structures. Furthermore, we investigated the correlation between the morphology and the luminescence characteristics of the GaN 1DNSs. Spatially and spectrally resolved cathodoluminescence (CL) measurements revealed that the relative near-band edge emission intensities of the GaN 1DNSs were 8–20 times higher than that of GaN thin film. In addition, pencil-like GaN 1DNSs exhibited 2.5-fold greater CL intensity than polygonal towerlike 1DNSs. These results indicate that controlling the surface morphology of GaN 1DNSs allows improvement in the optical properties of GaN nanostructures.
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81.16.-c Methods of micro- and nanofabrication and processing
68.35.bg Semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.46.-w Structure of nanoscale materials
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.60.Hk Cathodoluminescence, ionoluminescence
81.07.Bc Nanocrystalline materials

Electric field induced biaxiality and the electro-optic effect in a bent-core nematic liquid crystal

Mamatha Nagaraj, Y. P. Panarin, U. Manna, J. K. Vij, C. Keith, and C. Tschierske

Appl. Phys. Lett. 96, 011106 (2010); http://dx.doi.org/10.1063/1.3280817 (3 pages) | Cited 11 times

Online Publication Date: 7 January 2010

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We report the observation of a biaxial nematic phase in a bent-core molecular system using polarizing microscopy, electro-optics, and dielectric spectroscopy, where we find that the biaxiality exists on a microscopic scale. An application of electric field induces a macroscopic biaxiality and in consequence gives rise to electro-optic switching. This electro-optic effect shows significant potential in applications for displays due to its fast high-contrast response. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field.
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61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
78.20.Jq Electro-optical effects

Electrically driven quantum dot-micropillar single photon source with 34% overall efficiency

T. Heindel, C. Schneider, M. Lermer, S. H. Kwon, T. Braun, S. Reitzenstein, S. Höfling, M. Kamp, and A. Forchel

Appl. Phys. Lett. 96, 011107 (2010); http://dx.doi.org/10.1063/1.3284514 (3 pages) | Cited 31 times

Online Publication Date: 7 January 2010

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We report on triggered single photon emission from low mode volume electrically driven quantum dot-micropillar cavities at repetition rates of up to 220 MHz. Due to an optimized layout of the doped planar microcavity and an advanced lateral current injection scheme, highly efficient single photon sources are realized. While g(2)(0)-values as low as 0.13±0.05 and a Purcell factor of 4 are observed for a 2.0 μm diameter micropillar, single photon emission at a rate of (35±7) MHz and an overall efficiency of (34±7)% are demonstrated for a 3.0 μm device.
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78.60.Fi Electroluminescence
73.63.Kv Quantum dots
78.67.Hc Quantum dots
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Optical resonances created by photonic transitions

Zongfu Yu and Shanhui Fan

Appl. Phys. Lett. 96, 011108 (2010); http://dx.doi.org/10.1063/1.3279130 (3 pages)

Online Publication Date: 7 January 2010

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We show that a high-Q optical resonance can be created dynamically, by inducing a photonic transition between a localized state and a one-dimensional continuum through refractive index modulation. In this mechanism, both the frequency and the external linewidth of a single resonance are specified by the dynamics, allowing complete control of the resonance properties. An example using photonic crystal heterostructure cavity is demonstrated with numerical simulation. We also show that the reported effect can be accomplished with realistic index modulation strength and frequencies.
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42.79.Hp Optical processors, correlators, and modulators
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.70.Qs Photonic bandgap materials

Ultrafast gated imaging of laser produced plasmas using the optical Kerr effect

D. R. Symes, U. Wegner, H.-C. Ahlswede, M. J. V. Streeter, P. L. Gallegos, E. J. Divall, R. A. Smith, P. P. Rajeev, and D. Neely

Appl. Phys. Lett. 96, 011109 (2010); http://dx.doi.org/10.1063/1.3279139 (3 pages) | Cited 8 times

Online Publication Date: 7 January 2010

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Optical imaging is a versatile diagnostic for investigations of plasmas generated under intense laser irradiation. Electro-optic gating techniques operating on the >100 ps timescale are commonly used to reduce the amount of light detected from self-emission of hot plasma or improve the temporal resolution of the detector. The use of an optical Kerr gate enables a superior dynamic range and temporal resolution compared to electronically gated devices. The application of this method for enhanced imaging of laser produced plasmas with gate time ∼ 100 fs is demonstrated, and the possibility to produce a sub-10 fs, high dynamic range “all optical” streak camera is discussed.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
06.60.Jn High-speed techniques (microsecond to femtosecond)
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
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Time-resolved photoluminescence spectroscopy of an InGaAs/GaAs quantum well-quantum dots tunnel injection structure

M. Syperek, P. Leszczyński, J. Misiewicz, E. M. Pavelescu, C. Gilfert, and J. P. Reithmaier

Appl. Phys. Lett. 96, 011901 (2010); http://dx.doi.org/10.1063/1.3280384 (3 pages) | Cited 2 times

Online Publication Date: 4 January 2010

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Low temperature carrier dynamics in the InGaAs/GaAs quantum dot-based tunnel injection structure is studied by the time resolved photoluminescence experiment. We observed strongly modified photoluminescence kinetics between tunnel injection and reference quantum dot structures. Slowing down of the photoluminescence rise time in the tunnel injection system under weak and moderate excitation powers, we attributed to a fingerprint of a feeding process of quantum dot states with nonresonant carriers tunneling from the quantum well reservoir. We propose a simple three-level rate equation model to explain qualitatively the observed photoluminescence temporal behavior. Its result shows a good agreement with our experimental data.
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78.67.Hc Quantum dots
73.63.Kv Quantum dots
73.63.Hs Quantum wells
78.67.De Quantum wells
78.47.jd Time resolved luminescence
78.55.Cr III-V semiconductors

Influence of density on NH bond stretch vibration in plasma enhanced chemical vapor deposited SiNx:H

H. F. W. Dekkers, Nagendra Babu Srinivasan, and G. Pourtois

Appl. Phys. Lett. 96, 011902 (2010); http://dx.doi.org/10.1063/1.3281249 (3 pages) | Cited 2 times

Online Publication Date: 4 January 2010

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The infrared absorption of hydrogenated silicon nitride (SiNx:H) films provides information about the average configuration of covalent bonds in the film. In plasma enhanced chemical vapor deposited SiNx:H, the absorption spectrum of the NH bonds shows both a systematic shift and a tailing toward lower frequency with the increase in the film density. First-principles computations of NH vibrations show an increased degree of anharmonicity when the H site is weakly interacting with a second neighboring N atom. This interaction becomes more pronounced in films with higher density, which consequently shifts the vibrational spectrum down.
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78.30.Hv Other nonmetallic inorganics
52.77.Dq Plasma-based ion implantation and deposition
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
78.66.Nk Insulators
68.55.aj Insulators

Effect of thermal annealing on the blueshift of energy gap and nitrogen rearrangement in GaAsSbN

Yan-Ting Lin, Ta-Chun Ma, Hao-Hsiung Lin, Jiun-De Wu, and Ying-Sheng Huang

Appl. Phys. Lett. 96, 011903 (2010); http://dx.doi.org/10.1063/1.3282797 (3 pages) | Cited 5 times

Online Publication Date: 5 January 2010

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We report on the blueshift of energy gap and the nitrogen rearrangement resulting from the thermal treatment of GaAsSbN samples. The composition ranges of N and Sb are from 2% to 3% and from 7% to 11%, respectively. By comparing the photoluminescence peak energy and absorption energy gap, we found that the thermal annealing leads to compositional homogenization. When the annealing temperature is higher than 750 °C, the local vibration mode (LVM) absorbance of isolated substitutional nitrogen NAs starts to increase with the temperature. This finding supports the argument that nitrogen pairs thermally dissociate to isolated nitrogen. In additions, the increase of LVM absorbance accompanies the blueshift of energy gap, suggesting that the blueshift is the consequence of the nitrogen rearrangement. The decomposition of nitrogen pairs has also been observed by photoreflectance spectroscopy (PR). Multiple peaks were resolved from the PR spectra of as-grown GaAsSbN. They are relevant to transitions from regions with different nitrogen pairings and isolated nitrogen. As the annealing temperature increases, the peaks gradually merge to that of isolated nitrogen, indicating the decomposition of nitrogen pairings.
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81.05.Ea III-V semiconductors
78.55.Cr III-V semiconductors
61.72.Cc Kinetics of defect formation and annealing
81.40.Gh Other heat and thermomechanical treatments
78.20.-e Optical properties of bulk materials and thin films
63.20.-e Phonons in crystal lattices
71.20.Nr Semiconductor compounds

Micro-Raman spectroscopy of Si nanowires: Influence of diameter and temperature

A. Torres, A. Martín-Martín, O. Martínez, A. C. Prieto, V. Hortelano, J. Jiménez, A. Rodríguez, J. Sangrador, and T. Rodríguez

Appl. Phys. Lett. 96, 011904 (2010); http://dx.doi.org/10.1063/1.3284647 (3 pages) | Cited 4 times

Online Publication Date: 5 January 2010

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Raman spectroscopy provides nondestructive information about nanoscaled semiconductors by modeling the phonon confinement effect. However, the Raman spectrum is also sensitive to the temperature, which can mix with the size effects borrowing the interpretation of the Raman spectrum. We present an analysis of the Raman spectra of Si nanowires (NWs). The influence of the excitation conditions and the temperature increase in the NWs are discussed. The interpretation of the data is supported by the calculation of the temperature inside the NWs with different diameters.
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78.30.Am Elemental semiconductors and insulators
78.67.Lt Quantum wires
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves

Characteristic length scales governing plasticity/brittleness of bulk metallic glasses at ambient temperature

Y. Yang, J. C. Ye, J. Lu, P. K. Liaw, and C. T. Liu

Appl. Phys. Lett. 96, 011905 (2010); http://dx.doi.org/10.1063/1.3290246 (3 pages) | Cited 13 times

Online Publication Date: 6 January 2010

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In this letter, we propose a unified theory for the size-dependent plasticity of bulk metallic glasses (BMGs) at room temperature. Based on the principle of energy balance and the shear-banding kinetics, two characteristic length scales are derived. One is a sample-geometry dependent variable related to the elastic energy released to drive shear-band propagation and the other is a material-dependent constant related to the internal resistance to brittle fracture. It is shown that this unified theory is effective in explaining many unusual deformation and fracture behaviors of BMGs.
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81.40.Lm Deformation, plasticity, and creep
62.20.fq Plasticity and superplasticity
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.mm Fracture
62.20.D- Elasticity
61.43.Fs Glasses

Metamaterials on parylene thin film substrates: Design, fabrication, and characterization at terahertz frequency

X. Liu, S. MacNaughton, D. B. Shrekenhamer, H. Tao, S. Selvarasah, A. Totachawattana, R. D. Averitt, M. R. Dokmeci, S. Sonkusale, and W. J. Padilla

Appl. Phys. Lett. 96, 011906 (2010); http://dx.doi.org/10.1063/1.3275015 (3 pages) | Cited 8 times

Online Publication Date: 7 January 2010

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We design, fabricate, and characterize terahertz (THz) resonant metamaterials on parylene free-standing thin film substrates. Several different metamaterials are investigated and our results show strong electromagnetic responses at THz frequencies ranging from 500 GHz to 2.5 THz. The complex frequency dependent dielectric properties of parylene are determined from inversion of reflection and transmission data, thus indicating that parylene is an ideal low loss substrate or coating material. The biostable and biocompatible properties of parylene coupled with the multifunctional exotic properties of metamaterials indicate great potential for medical purposes such as THz imaging for skin cancer detection.
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42.70.Jk Polymers and organics
68.55.am Polymers and organics
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation
77.55.-g Dielectric thin films
78.70.Gq Microwave and radio-frequency interactions

Effects of subconduction band excitations on thermal conductance at metal-metal interfaces

Patrick E. Hopkins, Thomas E. Beechem, John C. Duda, Justin L. Smoyer, and Pamela M. Norris

Appl. Phys. Lett. 96, 011907 (2010); http://dx.doi.org/10.1063/1.3276908 (3 pages) | Cited 2 times

Online Publication Date: 8 January 2010

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Increased power densities combined with the decreased length scales of nanosystems give rise to large thermal excitations that can drastically affect the electron population near the Fermi surface. In light of such conditions, a model is developed for electron thermal boundary conductance (eTBC) that accounts for significant changes in the electron and hole populations around the Fermi level that occur at heightened temperatures. By including the contribution of subconduction band electrons to transport and evaluating the transmission coefficient based upon the total number of available states, an extension of eTBC predictions to high temperatures is made possible.
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73.20.At Surface states, band structure, electron density of states
73.40.-c Electronic transport in interface structures
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys
81.05.Bx Metals, semimetals, and alloys
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
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Graded composition and valence states in self-forming barrier layers at Cu–Mn/SiO2 interface

Y. Otsuka, J. Koike, H. Sako, K. Ishibashi, N. Kawasaki, S. M. Chung, and I. Tanaka

Appl. Phys. Lett. 96, 012101 (2010); http://dx.doi.org/10.1063/1.3269602 (3 pages) | Cited 9 times

Online Publication Date: 4 January 2010

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A self-forming diffusion barrier (SFB) layer was formed at Cu–Mn/SiO2 interface. Spatial variation of the chemical composition and valence state of the elements in the SFB was investigated in a subnanometer resolution using electron energy loss spectroscopy and transmission electron microscopy. The SFB was found to have a layered structure with graded compositions of nanocrystalline MnO and amorphous MnSiO3. The valence state of Mn was found to be +2 in the MnO layer and gradually increased to +3 in the MnSiO3 layer. The reported dielectric constant of the SFB could be explained by the observed composition and microstructure.
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68.35.Fx Diffusion; interface formation
66.30.-h Diffusion in solids
68.37.Lp Transmission electron microscopy (TEM)
77.22.Ch Permittivity (dielectric function)
82.80.-d Chemical analysis and related physical methods of analysis
79.20.Uv Electron energy loss spectroscopy

A polarity-controllable graphene inverter

Naoki Harada (原田直樹), Katsunori Yagi (八木克典), Shintaro Sato (佐藤信太郎), and Naoki Yokoyama (横山直樹)

Appl. Phys. Lett. 96, 012102 (2010); http://dx.doi.org/10.1063/1.3280042 (3 pages) | Cited 11 times

Online Publication Date: 4 January 2010

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We propose and experimentally demonstrate a functional electron device, which is a polarity-controllable inverter constructed using a four-terminal ambipolar graphene field effect transistor (FET). The FET has two input terminals, both a top gate and a back gate, and the polarity of the FET can be switched by switching the input to the back gate. The slope of the inverter transfer curves can be changed by changing the back-gate voltage. By adding binary digital data and sinusoidal carrier waves into the back gate and the top gate of the inverter, respectively, the one-transistor binary digital phase modulator can be constructed and operated.
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85.65.+h Molecular electronic devices
84.30.Jc Power electronics; power supply circuits
84.30.Qi Modulators and demodulators; discriminators, comparators, mixers, limiters, and compressors
85.30.Tv Field effect devices

Unipolar resistive switching effect in YMn1−δO3 thin films

Z. B. Yan, S. Z. Li, K. F. Wang, and J.-M. Liu

Appl. Phys. Lett. 96, 012103 (2010); http://dx.doi.org/10.1063/1.3280380 (3 pages) | Cited 8 times

Online Publication Date: 5 January 2010

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Steady unipolar resistive switching of Pt/YMn1−δO3/Pt MIM structure is investigated. High resistance ratio (>104) of high resistance state (HRS) over low resistance state (LRS) and long retention (>105 s) are achieved. It is suggested that the Joule heating and Poole–Frenkel effect dominate respectively the conduction of the LRS and HRS in high electric field region. The resistive switching is explained by the rupture and formation of conductive filaments in association with the local Joule-heat-induced redox inside YMn1−δO3.
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73.40.Rw Metal-insulator-metal structures
72.20.Ht High-field and nonlinear effects
73.61.Ng Insulators
68.55.aj Insulators
77.80.Fm Switching phenomena
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

Blinking suppression of single quantum dots in agarose gel

H. C. Ko, C. T. Yuan, S. H. Lin, and Jau Tang

Appl. Phys. Lett. 96, 012104 (2010); http://dx.doi.org/10.1063/1.3280386 (3 pages) | Cited 7 times

Online Publication Date: 5 January 2010

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Fluorescence blinking is commonly observed in single molecule/particle spectroscopy, but it is an undesirable feature in many applications. We demonstrated that single CdSe/ZnS quantum dots in agarose gel exhibited suppressed blinking behavior. In addition, the long-time exponential bending tail of the power-law blinking statistics was found to be influenced by agarose gel concentration. We suggest that electron transfer from the light state to the dark state might be blocked due to electrostatic surrounding of gel with inherent negatively charged fibers.
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78.67.Hc Quantum dots
82.70.Dd Colloids
82.70.Gg Gels and sols
78.55.Et II-VI semiconductors
78.55.Bq Liquids
82.30.Fi Ion-molecule, ion-ion, and charge-transfer reactions

Metal-organic chemical vapor deposition of high-dielectric-constant praseodymium oxide films using a cyclopentadienyl precursor

Hiroki Kondo, Shinnya Sakurai, Mitsuo Sakashita, Akira Sakai, Masaki Ogawa, and Shigeaki Zaima

Appl. Phys. Lett. 96, 012105 (2010); http://dx.doi.org/10.1063/1.3275706 (3 pages) | Cited 4 times

Online Publication Date: 6 January 2010

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Praseodymium (Pr) oxide films were grown by metal-organic chemical-vapor-deposition (CVD) using Pr(EtCp)3. Using H2O as an oxidant, Pr2O3 films with columnar structures are formed and its C concentration can be reduced to about one-tenth compared with the case using O2. Activation energy of 0.37 eV is derived for this CVD using H2O. This CVD-Pr oxide film deposited at 300 °C has a dielectric constant of 26±3. Furthermore, conduction band offset of 1.0±0.1 eV and trap levels of 0.40±0.02 and 0.22±0.02 eV in the CVD-Pr2O3/Si structure were also determined by current conduction characteristics.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
71.20.Ps Other inorganic compounds
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.D- High-permittivity gate dielectric films
68.55.aj Insulators
77.22.Ch Permittivity (dielectric function)

Influence of heavy doping on Seebeck coefficient in silicon-on-insulator

H. Ikeda and F. Salleh

Appl. Phys. Lett. 96, 012106 (2010); http://dx.doi.org/10.1063/1.3282783 (3 pages) | Cited 3 times

Online Publication Date: 6 January 2010

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We measured the Seebeck coefficient of heavily P-doped silicon-on-insulator layers with P concentrations above 1×1019 cm−3. The coefficient decreased with increasing P concentration, and with a peak of the Seebeck coefficient around 5×1019 cm−3. We calculated the density-of-states (DOS) of bulk Si based on theoretical models of impurity-band formation, ionization-energy shift, and conduction-band tailing. The calculated impurity-concentration dependence of the energy derivative of the DOS at the Fermi energy also showed a peak. Consequently, the Seebeck coefficient of the heavily doped Si is ruled by the DOS distribution, similar to metallic materials.
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73.50.Lw Thermoelectric effects
73.61.Cw Elemental semiconductors
61.72.uf Ge and Si
61.72.sd Impurity concentration
71.20.Mq Elemental semiconductors

Fabrication and characterization of metal-insulator-semiconductor structures by direct nitridation of InP surfaces

T. Haimoto, T. Hoshii, S. Nakagawa, M. Takenaka, and S. Takagi

Appl. Phys. Lett. 96, 012107 (2010); http://dx.doi.org/10.1063/1.3269906 (3 pages) | Cited 5 times

Online Publication Date: 7 January 2010

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We have fabricated InP metal-insulator-semiconductor (MIS) structures with direct nitridation of InP surfaces. The nitridation is performed by exposing InP surfaces to electron cyclotron resonance (ECR) N2 plasma. The formation of InP oxynitride layers with the thickness of around 1.5 nm is confirmed by transmission electron microscope images and x-ray photoelectron spectroscopy analysis. It is found that the surface nitridation drastically reduces the hysteresis of the C-V curves of SiO2/oxynitride/InP MIS capacitors, compared with the MIS capacitors without oxynitrides, indicating the reduction of slow traps inside InP native oxides. The nitridation under the rf power of 500 W can lead to the hysteresis down to 10 mV and the VFB shift down to −0.36 V. These results provide the experimental evidences for the effectiveness of ECR N2 plasma nitridation of InP and the insertion of the oxynitrided InP interfacial layers in terms of the InP MIS interface control.
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
76.40.+b Diamagnetic and cyclotron resonances
68.37.Lp Transmission electron microscopy (TEM)
79.60.Jv Interfaces; heterostructures; nanostructures
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Efficient spin injection into semiconductor from an Fe/GaOx tunnel injector

H. Saito, J. C. Le Breton, V. Zayets, Y. Mineno, S. Yuasa, and K. Ando

Appl. Phys. Lett. 96, 012501 (2010); http://dx.doi.org/10.1063/1.3282799 (3 pages) | Cited 5 times

Online Publication Date: 4 January 2010

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Show Abstract
We examined the electrical injection of spin-polarized electrons into a GaAs-based light-emitting diode structure from a Fe/GaOx tunnel injector whose electron-charge injection efficiency was comparable to that of a conventional Fe/n+-AlGaAs ohmic injector. A high circular polarization of electroluminescence up to 20% was observed at 2 K. The combination of effective spin-and charge-injection efficiencies makes GaOx a promising tunnel barrier for GaAs-based spintronic devices.
Show PACS
72.25.Dc Spin polarized transport in semiconductors
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
78.60.Fi Electroluminescence
85.60.Jb Light-emitting devices
72.25.Hg Electrical injection of spin polarized carriers
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