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

28 Jan 2008

Volume 92, Issue 4, Articles (04xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 92, 041901 (2008); http://dx.doi.org/10.1063/1.2831926 (3 pages)

M. A. Avila, K. Suekuni, K. Umeo, H. Fukuoka, S. Yamanaka, and T. Takabatake
Enlarge Image | Read More
Page 2 of 6 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

The dominant role of impurities in the composition of high pressure noble gas plasmas

T. Martens, A. Bogaerts, W. J. M. Brok, and J. V. Dijk

Appl. Phys. Lett. 92, 041504 (2008); http://dx.doi.org/10.1063/1.2839613 (3 pages) | Cited 28 times

Online Publication Date: 1 February 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present in this letter how a molecular gas such as nitrogen at different levels of impurity dominates the ionic composition of an atmospheric pressure noble gas plasma such as in helium. The positive charge in the discharge is only determined by helium ions if the discharge gas contains less than 1 ppm of impurity. Above this impurity level, the positive charge is completely determined by the impurity nitrogen. The higher the relative nitrogen concentration, the more N4+ dominates over N2+. If the impurity level is between 1 and about 20 ppm, N2+ is clearly the most abundant positive ion but for higher levels of impurity, N4+ almost completely determines the positive charge.
Show PACS
61.72.sd Impurity concentration
82.80.-d Chemical analysis and related physical methods of analysis
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
back to top
RSS Feeds

Ba8Ga16Sn30 with type-I clathrate structure: Drastic suppression of heat conduction

M. A. Avila, K. Suekuni, K. Umeo, H. Fukuoka, S. Yamanaka, and T. Takabatake

Appl. Phys. Lett. 92, 041901 (2008); http://dx.doi.org/10.1063/1.2831926 (3 pages) | Cited 31 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For the past decade, intermetallic clathrates have been rattling their way into mainstream research in thermoelectrics. The unusual vibrations of their guest ions inside oversized cages interfere with the cage phonons while leaving the electronic flow intact, providing an exotic way to achieve a best-of-both-worlds scenario in terms of electrical and thermal transport in the same material. Here, we present the structural and thermoelectric properties of Ba8Ga16Sn30 single crystals grown in the type-I clathrate structure (β-BGS), showing one of the lowest recorded thermal conductivities κ(T) for any bulk compound, while still behaving electronically as a heavily doped n-type semiconducting crystal.
Show PACS
72.20.Pa Thermoelectric and thermomagnetic effects
63.20.-e Phonons in crystal lattices
72.80.Jc Other crystalline inorganic semiconductors

Temperature effects on pinpoint photopolymerization and polymerized micronanostructures

Kenji Takada, Koshiro Kaneko, Yu-Dong Li, Satoshi Kawata, Qi-Dai Chen, and Hong-Bo Sun

Appl. Phys. Lett. 92, 041902 (2008); http://dx.doi.org/10.1063/1.2834365 (3 pages) | Cited 4 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The spatial resolution in pinpoint two-photon photopolymerization of radical-type resins was found to be improved by varying the liquid sample temperature from a critical value Tc. For SCR-500 and NOA-61, the currently widely used resins, Tc is around room temperature. The improvement of spatial resolution by temperature decrease was attributable to restraint radicals diffusion; while the voxel size reduction versus temperature increase was considered as arising from enhanced chain termination. Furthermore, temperature plays an important role in size tuning of polymerized structures, for example, a photonic crystal blueshifted its working wavelength for 50 and 400 nm when heated at 200 and 300 °C, respectively, indicating the possibility to precisely tailor the photonic bandgap by means of thermal processing.
Show PACS
82.35.-x Polymers: properties; reactions; polymerization
42.70.Jk Polymers and organics
81.07.Bc Nanocrystalline materials

The α-particle excited scintillation response of the liquid phase epitaxy grown LuAG:Ce thin films

P. Prusa, T. Cechak, J. A. Mares, M. Nikl, A. Beitlerova, N. Solovieva, Yu. V. Zorenko, V. I. Gorbenko, J. Tous, and K. Blazek

Appl. Phys. Lett. 92, 041903 (2008); http://dx.doi.org/10.1063/1.2835458 (3 pages) | Cited 13 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Liquid phase epitaxy grown Lu3Al5O12:Ce (LuAG:Ce) 20 μm thick films and plate cut from the bulk Czochralski-grown LuAG:Ce crystal were prepared for comparison of photoelectron yield (PhY) and PhY dependence on shaping time (0.5–10 μs). 241Am (α particles) was used for excitation. At the 0.5 μs shaping time, the best film shows comparable PhY with the bulk sample. PhY of bulk material increases noticeably more with shaping time than that of the films. Energy resolution of films is better. Influence of Pb2+ contamination in the films (from the flux) and antisite LuAl defect in bulk material is discussed.
Show PACS
78.60.-b Other luminescence and radiative recombination
61.80.Jh Ion radiation effects
61.72.U- Doping and impurity implantation
61.72.J- Point defects and defect clusters
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)

Compositional inhomogeneity of a high-efficiency InxGa1−xN based multiple quantum well ultraviolet emitter studied by three dimensional atom probe

M. J. Galtrey, R. A. Oliver, M. J. Kappers, C. McAleese, D. Zhu, C. J. Humphreys, P. H. Clifton, D. Larson, and A. Cerezo

Appl. Phys. Lett. 92, 041904 (2008); http://dx.doi.org/10.1063/1.2829592 (3 pages) | Cited 8 times

Online Publication Date: 29 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An InxGa1−xN based multiple quantum well structure emitting in the ultraviolet, which has the highest reported efficiency (67%) at its wavelength (380 nm), was analyzed with the three-dimensional atom probe. The results reveal gross discontinuities and compositional variations within the quantum well layers on a 20–100 nm length scale. In addition, the analysis shows the presence of indium in the AlyGa1−yN barrier layers, albeit at a very low level. By comparing with analogous epilayer samples, we suggest that the quantum well discontinuities we observe may play an important role in improving the efficiency of these structures.
Show PACS
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
85.60.Jb Light-emitting devices

High tensile strength reliability in a bulk metallic glass

J. H. Yao, J. Q. Wang, L. Lu, and Y. Li

Appl. Phys. Lett. 92, 041905 (2008); http://dx.doi.org/10.1063/1.2838715 (3 pages) | Cited 10 times

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report high strength reliability under tension of a bulk metallic glass (BMG), demonstrated by its high uniformity in strength found over a statistically significant number of specimens, despite the fact that the samples all showed no macroscopic plasticity. Weibull statistical analysis showed that the Weibull modulus of the material is 36.5, which is much higher than the values of more typical brittle materials, further confirming BMGs’ high reliability [ Appl. Mech. Rev. 5, 449 (1952) ].
Show PACS
81.40.Lm Deformation, plasticity, and creep
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.70.Bt Mechanical testing, impact tests, static and dynamic loads
62.20.de Elastic moduli
62.20.F- Deformation and plasticity

Experimental analysis for the effect of dynamic capillarity on stress transformation in porous silicon

Wei Qiu, Yi-Lan Kang, Qiu Li, Zhen-Kun Lei, and Qing-Hua Qin

Appl. Phys. Lett. 92, 041906 (2008); http://dx.doi.org/10.1063/1.2838716 (3 pages) | Cited 3 times

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The evolution of real-time stress in porous silicon (PS) during drying is investigated using micro-Raman spectroscopy. The results show that the PS sample underwent non-negligible stress when immersed in liquid and suffered a stress impulsion during drying. Such nonlinear transformation and nonhomogeneneous distribution of stress are regarded as the coupling effects of several physical phenomena attributable to the intricate topological structure of PS. The effect of dynamic capillarity can induce microcracks and even collapse in PS structures during manufacture and storage.
Show PACS
81.05.Cy Elemental semiconductors
81.05.Rm Porous materials; granular materials
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.mt Cracks
78.30.Am Elemental semiconductors and insulators

Rheological behavior probed by vibrating microcantilevers

Naser Belmiloud, Isabelle Dufour, Annie Colin, and Liviu Nicu

Appl. Phys. Lett. 92, 041907 (2008); http://dx.doi.org/10.1063/1.2837181 (3 pages) | Cited 8 times

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The aim of this paper is to demonstrate that vibrating microcantilevers can be used to quantify fluid properties such as density and viscosity. Contrary to classical rheological measurements using microcantilevers, the development of the proposed microrheometer is based on the measurement of fluid properties over a range of vibration frequencies, without necessarily being restricted to resonant phenomena. To this end, an analytical model is implemented and, when combined with measurements, allows the determination of the viscosity as a function of frequency. The preliminary results are encouraging for the development of a useful microrheometer on a silicon chip for microfluidic applications.
Show PACS
47.80.-v Instrumentation and measurement methods in fluid dynamics
47.85.Np Fluidics

Study of thermal stability and luminescence quenching properties of bismuth-doped silicate glasses for fiber laser applications

V. G. Truong, L. Bigot, A. Lerouge, M. Douay, and I. Razdobreev

Appl. Phys. Lett. 92, 041908 (2008); http://dx.doi.org/10.1063/1.2828035 (3 pages) | Cited 46 times

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In the present work, we report on the luminescence properties of bismuth-doped silicate preforms and fibers under the influence of high temperature annealing and hydrogen-loading then annealing processes. Bismuth-related luminescence is found to be very sensitive to thermal annealing processes and can even totally disappear for specific annealing processes. The observed quenching of the luminescence was attributed to the reduction of part of bismuth ions responsible for the infrared luminescence into a lower valence state of bismuth.
Show PACS
42.70.Ce Glasses, quartz
78.55.Hx Other solid inorganic materials

First-principles study of structural, elastic, and electronic properties of chromium carbides

Chao Jiang

Appl. Phys. Lett. 92, 041909 (2008); http://dx.doi.org/10.1063/1.2838345 (3 pages) | Cited 23 times

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using first-principles calculations, we systematically studied the structural, elastic, and electronic properties of the technologically important chromium carbides: Cr3C2, Cr7C3, Cr23C6, Cr3C, and CrC. Our calculations show that the ground state structure for Cr7C3 is hexagonal, not orthorhombic. We further predict WC to be the energetically most stable structure for CrC. Our results indicate that all chromium carbides considered in this study are metallic and mechanically stable under the ambient condition. Among all chromium carbides, WC-type CrC exhibits the highest bulk and shear moduli and the lowest Poisson’s ratio, and is a potential low-compressibility and hard material.
Show PACS
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Lm Deformation, plasticity, and creep
62.20.de Elastic moduli
62.20.dj Poisson's ratio
62.20.F- Deformation and plasticity
71.20.Ps Other inorganic compounds
71.15.-m Methods of electronic structure calculations

Room temperature contactless electroreflectance of the ground and excited state transitions in Ga0.76In0.24As0.08Sb0.92/GaSb single quantum wells of various widths

R. Kudrawiec, M. Motyka, J. Misiewicz, M. Hümmer, K. Rößner, T. Lehnhardt, M. Müller, and A. Forchel

Appl. Phys. Lett. 92, 041910 (2008); http://dx.doi.org/10.1063/1.2840161 (3 pages) | Cited 9 times

Online Publication Date: 31 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical transitions in Ga0.76In0.24As0.08Sb0.92/GaSb quantum wells with the width varying from 10 to 21 nm were studied by room temperature contactless electroreflectance (CER). In addition to the quantum well (QW) ground state transition (11H), the 22H and 33H transitions (where klH denotes transition between the kth heavy hole and the lth electron subbands) have been clearly observed in CER spectra. The experimental QW transition energies were compared with theoretical predictions based on an effective mass formalism model. It has been concluded that this QW is type I for both electron and holes and the conduction band offset for the unstrained Ga0.76In0.24As0.08Sb0.92/GaSb interface equals ∼ 90%.
Show PACS
78.20.Jq Electro-optical effects
78.67.De Quantum wells
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
73.21.Fg Quantum wells

The influence of substrate polarity on the structural quality of InN layers grown by high-pressure chemical vapor deposition

N. Dietz, M. Alevli, R. Atalay, G. Durkaya, R. Collazo, J. Tweedie, S. Mita, and Z. Sitar

Appl. Phys. Lett. 92, 041911 (2008); http://dx.doi.org/10.1063/1.2840192 (3 pages) | Cited 6 times

Online Publication Date: 31 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of substrate polarity on the properties of InN layers grown by high-pressure chemical vapor deposition has been studied. The 2Θ-ω x-ray diffraction scans on InN layers deposited on polar GaN epilayers revealed single-phase InN(0002) with a full width at half maximum (FWHM) of around 200 arc sec. InN layers grown on N-polar GaN exhibit larger FWHMs. Rocking curve analysis confirmed single-phase InN for both growth polarities, with FWHM values for ω-RC(002) at 2080 arc sec for InN grown on Ga-polar templates. The A1(LO) Raman mode analysis shows higher free carrier concentrations in InN grown on N-polar templates, indicating that polarity affects the incorporation of impurities.
Show PACS
68.55.J- Morphology of films
68.55.ag Semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
78.66.Fd III-V semiconductors
78.30.Fs III-V and II-VI semiconductors

Flexible all-solid-state switchable mirror on plastic sheet

Kazuki Tajima, Yasusei Yamada, Shanhu Bao, Masahisa Okada, and Kazuki Yoshimura

Appl. Phys. Lett. 92, 041912 (2008); http://dx.doi.org/10.1063/1.2839298 (3 pages) | Cited 18 times

Online Publication Date: 31 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We developed all-solid-state switchable mirror on flexible plastic [polyethylene terephthalate (PET)] sheet in the view point of low process cost and easy handling. Its optical switching property was investigated. Though the device on PET sheet showed over 4000 cycles of switching in durability test, it was lower than that on glass. The reasons seemed to be related with heterogeneous structure, oxidation of surface layer and adhesion of the film. However, it remarkably results that the device on plastic sheet showed such a high durability nonetheless because the sheet is weak to mechanical stress.
Show PACS
42.82.Gw Other integrated-optical elements and systems
42.79.Bh Lenses, prisms and mirrors
42.82.Bq Design and performance testing of integrated-optical systems
42.65.Pc Optical bistability, multistability, and switching, including local field effects
42.87.-d Optical testing techniques

Formation of two conjoint fivefold deformation twins in copper nanowires with molecular dynamics simulation

Y. G. Zheng, H. W. Zhang, Z. Chen, L. Wang, Z. Q. Zhang, and J. B. Wang

Appl. Phys. Lett. 92, 041913 (2008); http://dx.doi.org/10.1063/1.2839581 (3 pages) | Cited 9 times

Online Publication Date: 31 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The formation of two conjoint fivefold deformation twins (DTs) in copper nanowires under bending is reported based on molecular dynamics simulations. It is found that an intermediate icosahedral phase is formed to facilitate the transformation from a low dense (010) plane in a face-centered-cubic lattice to a {111} close-packed fashion, forming trijunctions composed of three DTs. These trijunctions can easily interact with other DTs, forming two conjoint fivefold DTs. This formation process differs from the one observed by Cao and Wei [Appl. Phys. Lett. 89, 041919 (2006)] , that is, fivefold DTs could be formed without introducing initial imperfections in simulations.
Show PACS
64.70.Nd Structural transitions in nanoscale materials
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)
61.72.Mm Grain and twin boundaries
62.23.Hj Nanowires
61.44.Br Quasicrystals

Colorizing metals with femtosecond laser pulses

A. Y. Vorobyev and Chunlei Guo

Appl. Phys. Lett. 92, 041914 (2008); http://dx.doi.org/10.1063/1.2834902 (3 pages) | Cited 67 times

Online Publication Date: 31 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For centuries, it had been the dream of alchemists to turn inexpensive metals into gold. Certainly, it is not enough from an alchemist’s point of view to transfer only the appearance of a metal to gold. However, the possibility of rendering a certain metal to a completely different color without coating can be very interesting in its own right. In this work, we demonstrate a femtosecond laser processing technique that allows us to create a variety of colors on a metal that ultimately leads us to control its optical properties from UV to terahertz.
Show PACS
81.05.Bx Metals, semimetals, and alloys
42.62.-b Laser applications
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Discrimination of quantum dots using an optically created nuclear field

H. Sasakura, R. Kaji, S. Adachi, and S. Muto

Appl. Phys. Lett. 92, 041915 (2008); http://dx.doi.org/10.1063/1.2839615 (3 pages) | Cited 2 times

Online Publication Date: 1 February 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated an optically created nuclear field in a single InAlAs quantum dot and demonstrated that the nuclear field can be used to discriminate whether photoluminescence lines originate from the same dot or a different dot. Since the nonlinear response of the nuclear field is sensitive to the electron g factor and correlation time of a coupled electron-nuclear spin system, the resultant Overhauser shift is their good measure for individual quantum dots. This method provides a simple and convenient alternative to the standard photon cross-correlation method.
Show PACS
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
72.25.Fe Optical creation of spin polarized carriers
back to top
RSS Feeds

Auger recombination in InN thin films

D.-J. Jang, G.-T. Lin, C.-L. Hsiao, L. W. Tu, and M.-E. Lee

Appl. Phys. Lett. 92, 042101 (2008); http://dx.doi.org/10.1063/1.2837537 (3 pages) | Cited 9 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Auger recombination is studied in InN thin films using an ultrafast time-resolved photoluminescence apparatus. The decay rates are analyzed with nonlinear dependence of the photoluminescence intensity on the carrier concentration. The fitted radiative recombination coefficients at a temperature of 35 K are consistent with the theoretical prediction. The Auger rates are small at low carrier concentrations but increase quadratically with the carrier concentration. The Auger activation energies of 4.3 and 9.0 meV obtained from the temperature-dependent Auger coefficient indicate that Auger recombination is weakly dependent on temperature and is a phonon-assisted process.
Show PACS
73.61.Le Other inorganic semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
68.55.ag Semiconductors
78.66.Li Other semiconductors
78.55.Hx Other solid inorganic materials
79.20.Fv Electron impact: Auger emission

Nanoampere charge pump by single-electron ratchet using silicon nanowire metal-oxide-semiconductor field-effect transistor

Akira Fujiwara, Katsuhiko Nishiguchi, and Yukinori Ono

Appl. Phys. Lett. 92, 042102 (2008); http://dx.doi.org/10.1063/1.2837544 (3 pages) | Cited 25 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanoampere single-electron pumping is presented at 20 K using a single-electron ratchet comprising silicon nanowire metal-oxide-semiconductor field-effect transistors. The ratchet features an asymmetric potential with a pocket that captures single electrons from the source and ejects them to the drain. Directional single-electron transfer is achieved by applying one ac signal with the frequency up to 2.3 GHz. We find anomalous shapes of current steps which can be ascribed to nonadiabatic electron capture.
Show PACS
85.30.Tv Field effect devices
85.35.Gv Single electron devices

Multilevel charging and discharging mechanisms of vertically stacked Ni1−xFex self-assembled nanoparticle arrays embedded in polyimide layers

T. W. Kim, J. H. Jung, C. S. Yoon, and Y.-H. Kim

Appl. Phys. Lett. 92, 042103 (2008); http://dx.doi.org/10.1063/1.2838300 (3 pages) | Cited 4 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Capacitance-voltage curves for the Al/polyimide (PI)/multilayered Ni1−xFex nanoparticle array/PI/p-Si (100) devices at 300 K showed that the flatband voltage shift of the metal-insulator-semiconductor capacitor was affected by the value of sweep voltage, indicative of the variations in the charged electron number in the multiple-stacked Ni1−xFex nanoparticle arrays in the floating gate. Current-voltage results showed that the electron charging and discharging in the Ni1−xFex nanoparticles were attributed to thermionic emission and Fowler-Nordheim tunneling, respectively. The multilevel charging and discharging mechanisms of vertically stacked Ni1−xFex self-assembled nanoparticle arrays embedded in PI layers are described on the basis of the experimental results.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.40.Gk Tunneling
81.16.Dn Self-assembly
79.40.+z Thermionic emission
84.32.Tt Capacitors

Tunable pure spin currents in a triple-quantum-dot ring

Weijiang Gong, Yisong Zheng, and Tianquan Lü

Appl. Phys. Lett. 92, 042104 (2008); http://dx.doi.org/10.1063/1.2838310 (3 pages) | Cited 27 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electronic transport through a triple-quantum-dot ring with three terminals is theoretically studied. By introducing local Rashba spin-orbit interaction on an individual quantum dot, we calculate the charge and spin currents in one lead. We find that a pure spin current without an accompanying charge current appears even at zero magnetic field case. The polarization direction of the spin current can be inverted by altering the bias voltage. In addition, by tuning the magnetic field strength, the charge and spin currents reach their respective peaks alternately.
Show PACS
73.63.Kv Quantum dots
72.25.-b Spin polarized transport
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect

Studies of oxide/ZnO near-interfacial defects by photoluminescence and deep level transient spectroscopy

R. S. Wang, Q. L. Gu, C. C. Ling, and H. C. Ong

Appl. Phys. Lett. 92, 042105 (2008); http://dx.doi.org/10.1063/1.2838326 (3 pages) | Cited 5 times

Online Publication Date: 28 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The evolution of near-interfacial defects from Al2O3/ZnO and MgO/ZnO upon thermal annealing has been studied by photoluminescence, deep level transient spectroscopy, and secondary ion mass spectroscopy. We find that all the results are strongly connected and that they point to the direction that Zn outdiffuses from ZnO to the oxide layer during annealing and creates deep level defects near the interfacial region. These defects reduce the band-edge emission and increase the deep level emission at 2.37 eV. Our study shows that the oxide/ZnO interface is relatively fragile and caution must be taken for making metal-oxide-ZnO based transistors and light emitting diodes.
Show PACS
68.35.Ct Interface structure and roughness
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
78.55.Et II-VI semiconductors
61.72.Cc Kinetics of defect formation and annealing
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Effect of oxygen on the electronic configuration of Gd2O3/Ge heterojunctions

M. Perego, A. Molle, and M. Fanciulli

Appl. Phys. Lett. 92, 042106 (2008); http://dx.doi.org/10.1063/1.2838344 (3 pages) | Cited 6 times

Online Publication Date: 29 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The band structure of the Gd2O3/Ge heterojunction was investigated by x-ray photoelectron spectroscopy and was found to be very sensitive to variations of oxygen content in the oxide film. A 0.6 eV decrease of the valence band offset (VBO) has been observed after in situ O2 postdeposition annealing (PDA). The VBO value obtained after PDA is 2.8 eV in excellent agreement with data reported in the literature. The extra oxygen, supplied during PDA, is stably incorporated in the Gd2O3 matrix. Moreover, this extra oxygen limits moisture adsorption during air exposure and helps to stabilize the electronic configuration of the Gd2O3/Ge heterojunction.
Show PACS
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.20.At Surface states, band structure, electron density of states
79.60.Jv Interfaces; heterostructures; nanostructures
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Transition from direct tunneling to field emission in carbon nanotube intramolecular junctions

Po-Wen Chiu and Siegmar Roth

Appl. Phys. Lett. 92, 042107 (2008); http://dx.doi.org/10.1063/1.2838353 (3 pages) | Cited 6 times

Online Publication Date: 29 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Transport measurements through metal-semiconductor carbon nanotube intramolecular junctions were carried out at high gate voltages in which regime the influence of Schottky barrier to charge transport is weak. The I-Vds curves exhibit an inflection point in the form of ln(I/Vds2)−1/Vds, showing a transition of transport mechanism from direct tunneling to field emission. The findings are interpreted in terms of quantum tunneling through a rectanglelike barrier at the junction, with a barrier width of ∼ 4 nm, in good agreement with that observed on pentagon-heptagon defects at nanotube junctions via scanning tunneling spectroscopy.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.40.Gk Tunneling
73.30.+y Surface double layers, Schottky barriers, and work functions
79.70.+q Field emission, ionization, evaporation, and desorption

Suppression of the orientation effects on bandgap in graphene nanoribbons in the presence of edge disorder

D. Querlioz, Y. Apertet, A. Valentin, K. Huet, A. Bournel, S. Galdin-Retailleau, and P. Dollfus

Appl. Phys. Lett. 92, 042108 (2008); http://dx.doi.org/10.1063/1.2838354 (3 pages) | Cited 38 times

Online Publication Date: 29 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter shows that a moderate degree of edge disorder can explain the fact that the experimentally measured bandgaps of graphene nanoribbons (GNRs) do not depend on orientation. We argue that GNRs actually behave similarly to Anderson insulators and the measured bandgaps should thus be interpreted as quasi-mobility edges. Calculations in the tight binding approach reveal that in the presence of edge disorder, quasi-mobility edge and electronic structures become independent of orientation and that quasi-mobility edge follows a quasi-universal law similar to experimental data, although with different parameters.
Show PACS
73.22.-f Electronic structure of nanoscale materials and related systems
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)

In situ arsenic-doped Si1−yCy selective epitaxial growth under atmospheric pressure

Tetsuya Ikuta, Shigeru Fujita, Hayato Iwamoto, Shingo Kadomura, Takayoshi Shimura, Heiji Watanabe, and Kiyoshi Yasutake

Appl. Phys. Lett. 92, 042109 (2008); http://dx.doi.org/10.1063/1.2838724 (3 pages)

Online Publication Date: 30 January 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated the characteristics of in situ As-doped Si1−yCy selective epitaxial growth (SEG) under atmospheric pressure. We succeeded in obtaining an in situ doped Si1−yCy SEG film with a high As concentration of 2.6×1019 atoms/cm3. The film exhibited a high crystalline quality, high strain, constant As and C concentration profiles, and an abrupt change in the dopant profile at the interface. It was found that the increase in As concentration under atmospheric pressure increases the C concentration and the growth rate by competitive surface segregation between As and C atoms, leading to a highly strained Si1−yCy SEG film with a low resistivity.
Show PACS
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.ag Semiconductors
68.35.Dv Composition, segregation; defects and impurities
61.72.up Other materials
73.61.Le Other inorganic semiconductors
Page 2 of 6 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close