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

7 Sep 2009

Volume 95, Issue 10, Articles (10xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 083506 (2009); http://dx.doi.org/10.1063/1.3216851 (3 pages)

J. Z. Sun, M. C. Gaidis, E. J. O’Sullivan, E. A. Joseph, G. Hu, D. W. Abraham, J. J. Nowak, P. L. Trouilloud, Yu Lu, S. L. Brown, D. C. Worledge, and W. J. Gallagher

Publisher's Note

Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Intrinsic and boron-enhanced hydrogen diffusion in amorphous silicon formed by ion implantation

B. C. Johnson, J. C. McCallum, A. J. Atanacio, and K. E. Prince

Appl. Phys. Lett. 95, 101911 (2009); http://dx.doi.org/10.1063/1.3224189 (3 pages) | Cited 3 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The concentration dependence of H diffusion in amorphous Si (a-Si) formed by ion implantation is reported for implanted H profiles. An empirical relationship is proposed which relates the diffusion coefficient to the H concentration valid up to 0.3 at. %. B-enhanced H diffusion is observed and shows trends with temperature typically associated with a Fermi level shifting dependence. A modified form of the generalized Fermi level shifting model is applied to these data.
Show PACS
66.30.H- Self-diffusion and ionic conduction in nonmetals
61.72.uf Ge and Si
71.20.Mq Elemental semiconductors
back to top
RSS Feeds

Room temperature ferromagnetism of bulk polycrystalline (In0.85−xSnxFe0.15)2O3: Charge carrier mediated or oxygen vacancy mediated?

S. C. Li, P. Ren, B. C. Zhao, B. Xia, and L. Wang

Appl. Phys. Lett. 95, 102101 (2009); http://dx.doi.org/10.1063/1.3222867 (3 pages) | Cited 8 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Four bulk polycrystalline (In0.85−xSnxFe0.15)2O3 samples with x = 0, 0.01, 0.03, and 0.05 were synthesized, where carrier concentration n was controlled by varying Sn doping concentration x. Strong room temperature ferromagnetism was observed. A systematic characterization and analysis of structure, purity, magnetic, and transport properties indicates that ferromagnetism is due to neither impurities nor charge carriers. The four samples were annealed in air and high vacuum alternately. The ferromagnetism signal disappears and appears accordingly. Based on these results, we conclude that room temperature ferromagnetism in (In0.85−xSnxFe0.15)2O3 system is closely and directly related to oxygen vacancies in the samples.
Show PACS
61.72.jd Vacancies
61.72.up Other materials
75.50.Pp Magnetic semiconductors
81.05.Hd Other semiconductors
72.80.Jc Other crystalline inorganic semiconductors
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
61.72.Cc Kinetics of defect formation and annealing
72.20.Fr Low-field transport and mobility; piezoresistance

Amorphous carbon and carbon nitride bottom gate thin film transistors

Y. Miyajima, M. Shkunov, and S. R. P. Silva

Appl. Phys. Lett. 95, 102102 (2009); http://dx.doi.org/10.1063/1.3224834 (3 pages) | Cited 8 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Carbon based bottom gate thin film transistors were fabricated using pulsed laser deposited amorphous carbon (a-C) and amorphous carbon nitride (a-CNx) films. Both series of devices show p-type conduction in the active channel at high electric fields, for which the conduction mechanism may be fitted to Poole–Frenkel type behavior. The field effect mobilities were estimated to values of 2.5×10−3 cm2 V−1 S−1 at high fields. Nitrogen inclusion does not appear to affect the performance of the a-CNx at high fields since the current is postulated to be controlled by hole conduction states.
Show PACS
85.30.Tv Field effect devices
61.43.Er Other amorphous solids
81.15.Fg Pulsed laser ablation deposition
66.30.H- Self-diffusion and ionic conduction in nonmetals
72.20.Ht High-field and nonlinear effects
73.50.Fq High-field and nonlinear effects
61.72.Qq Microscopic defects (voids, inclusions, etc.)
71.20.Ps Other inorganic compounds

Graphene on gallium arsenide: Engineering the visibility

M. Friedemann, K. Pierz, R. Stosch, and F. J. Ahlers

Appl. Phys. Lett. 95, 102103 (2009); http://dx.doi.org/10.1063/1.3224910 (3 pages) | Cited 7 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Graphene consists of single or few layers of crystalline ordered carbon atoms. Its visibility on oxidized silicon (Si/SiO2) enabled its discovery and spawned numerous studies of its unique electronic properties. The combination of graphene with the equally unique electronic material gallium arsenide (GaAs) has up to now lacked such easy visibility. Here we demonstrate that a deliberately tailored GaAs-aluminum arsenide (AlAs) multilayer structure makes graphene just as visible on GaAs as on Si/SiO2. We show that standard microscope images of exfoliated graphite on GaAs/AlAs suffice to identify mono-, bi-, and multilayers of graphene. Raman data confirm our results.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
71.20.Tx Fullerenes and related materials; intercalation compounds
78.30.Na Fullerenes and related materials
73.21.Ac Multilayers

Investigation on −c-InN and a-InN:Mg field effect transistors under electrolyte gate bias

Yen-Sheng Lu, Yuh-Hwa Chang, Yu-Liang Hong, Hong-Mao Lee, Shangjr Gwo, and J. Andrew Yeh

Appl. Phys. Lett. 95, 102104 (2009); http://dx.doi.org/10.1063/1.3216064 (3 pages) | Cited 1 time

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electrical properties of N-polar undoped InN and nonpolar a-InN:Mg ion sensitive field effect transistors (ISFETs) have been investigated by electrolyte-gate-biased current-voltage (IDS-VGS) measurements. IDS-VGS characteristics reveal that the a-InN:Mg ISFETs have a large ( ∼ 52%) current variation ratio at a gate bias of 0.3 V with respect to the unbiased one, which is higher than that from the undoped InN ISFETs ( ∼ 18% and <0.1% for 10-nm and 1-μm-thick −c-InN epilayers, respectively). The a-InN:Mg ISFETs can also function as a pH sensor with a sensitivity of 56.5 mV/pH and a response time less than 10 s.
Show PACS
85.30.Tv Field effect devices
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Nanofluidic electrokinetics in nanoparticle crystal

Zhen Chen, Yunshan Wang, Wei Wang, and Zhihong Li

Appl. Phys. Lett. 95, 102105 (2009); http://dx.doi.org/10.1063/1.3223774 (3 pages) | Cited 6 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We scrutinize experimentally and theoretically the electrokinetics of a nanochannel network in a nanoparticle crystal. Conductance of the nanochannel network, a function of concentrations of the loaded electrolyte solutions, exhibits typical electrokinetic properties of individual nanochannel but with a much larger electrical signal. A widely accepted electrokinetic equation is used to elucidate the origin of the high throughput from a top-down perspective. Using a bottom-up analysis, a stepwise modeling process from individual nanochannel to highly ordered nanochannel network is proposed to render an in-depth view of the nanofluidics network.
Show PACS
47.61.Fg Flows in micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS)
47.60.Dx Flows in ducts and channels
47.85.Np Fluidics
82.45.Gj Electrolytes

Subband transitions in dual-band n-B-n InAs/GaSb superlattice infrared photodetector identified by photoresponse spectra

S. J. Lee, S. K. Noh, E. Plis, S. Krishna, and K.-S. Lee

Appl. Phys. Lett. 95, 102106 (2009); http://dx.doi.org/10.1063/1.3212738 (3 pages) | Cited 5 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The subband transitions in dual-band n-B-n InAs/GaSb type-II superlattice infrared photodetector are identified by the photoresponse (PR) spectra. In the mid- and long-wavelength PR spectra measured by changing bias polarity, each spectrum individually shows a series of distinctive peaks related to the transitions from the hole subbands to the conduction one. The PR mechanism at each polarity is discussed in terms of diffusion and tunneling currents.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors

Size-dependent interface band alignment between Si nanocrystals and lattice-matched Gd2O3

V. V. Afanas’ev, M. Badylevich, A. Stesmans, A. Laha, H. J. Osten, and A. Fissel

Appl. Phys. Lett. 95, 102107 (2009); http://dx.doi.org/10.1063/1.3204019 (3 pages) | Cited 3 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicon nanocrystals embedded in a lattice-matched Gd2O3 matrix exhibit large size-dependent bandgap widening. Measurements of photocharging spectra of these crystals indicate only a marginal variation in the photoionization threshold energy. The latter suggests that most of the confinement-induced bandgap width variation is caused by the upward shift of the Si nanocrystal conduction band bottom.
Show PACS
73.20.At Surface states, band structure, electron density of states
71.20.Mq Elemental semiconductors
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
72.40.+w Photoconduction and photovoltaic effects

Pseudospin filter for graphene via laser irradiation

J. C. Martinez, M. B. A. Jalil, and S. G. Tan

Appl. Phys. Lett. 95, 102108 (2009); http://dx.doi.org/10.1063/1.3220067 (3 pages) | Cited 2 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study graphene monolayer charge carriers irradiated by an electromagnetic vortex. From this, two scenarios are envisaged: canonical oscillator coherent states, which form for large particle numbers and from which a sublattice filter can be constructed, and pair-coherent states, which emerge when the carrier velocity is much less than the Fermi velocity and which can exhibit nonclassical properties. The first should be useful in the control (e.g., confinement and guided transport) of graphene electrons, while the second provides a physical system for examining nonclassical properties of wave packets.
Show PACS
73.63.Bd Nanocrystalline materials
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
back to top
RSS Feeds

The origins of ferromagnetism in Co-doped ZnO single crystalline films: From bound magnetic polaron to free carrier-mediated exchange interaction

Z. L. Lu, H. S. Hsu, Y. H. Tzeng, F. M. Zhang, Y. W. Du, and J. C. A. Huang

Appl. Phys. Lett. 95, 102501 (2009); http://dx.doi.org/10.1063/1.3224911 (3 pages) | Cited 17 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-quality Co-doped ZnO single crystalline films with a wide range of carrier concentration and good reproducibility have been grown by molecular beam epitaxy. After the systematic studies of the magnetic and transport properties of the films, we suggest that there are two distinct ferromagnetic mechanisms in different conductivity regimes. In the insulating regime, carriers tend to be localized, favoring the formation of bound magnetic polarons, which leads to ferromagnetism. In the metallic regime, however, most carriers are weakly localized and the free carrier-mediated exchange is dominant. Our experimental observations are well consistent with the recent theoretical description of magnetism in Co-doped ZnO and helpful for understanding the ferromagnetic mechanism in oxide-based diluted magnetic semiconductors.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
68.55.ag Semiconductors
75.30.Et Exchange and superexchange interactions
71.38.-k Polarons and electron-phonon interactions
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials

Six-fold in-plane magnetic anisotropy in Co-implanted ZnO (0001)

Numan Akdoğan, Bulat Rameev, Sümeyra Güler, Osman Öztürk, Bekir Aktaş, Hartmut Zabel, Rustam Khaibullin, and Lenar Tagirov

Appl. Phys. Lett. 95, 102502 (2009); http://dx.doi.org/10.1063/1.3223583 (3 pages) | Cited 5 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetic anisotropies of Co-implanted ZnO (0001) films grown on single-crystalline Al2O3 (11math0) substrates have been studied by ferromagnetic resonance (FMR) technique for different cobalt implantation doses. The FMR data show that the easy and hard axes have a periodicity of 60° in the film plane, in agreement with the hexagonal structure of the ZnO films. This six-fold in-plane magnetic anisotropy, which is observed for the first time in ZnO-based diluted magnetic semiconductors, is attributed to the substitution of cobalt on Zn sites in the ZnO structure, and a clear indication for long range ferromagnetic ordering between substitutional cobalt ions in the single-crystalline ZnO films.
Show PACS
75.30.Gw Magnetic anisotropy
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Pp Magnetic semiconductors
68.55.ag Semiconductors
81.05.Dz II-VI semiconductors
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.uj III-V and II-VI semiconductors

Highly luminescent garnets for magneto-optical photonic crystals

A. M. Grishin and S. I. Khartsev

Appl. Phys. Lett. 95, 102503 (2009); http://dx.doi.org/10.1063/1.3224204 (3 pages) | Cited 3 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We compare luminescent properties of several Er-doped garnets as building blocks in all-garnet heteroepitaxial magneto-optical photonic crystals. Pulsed laser deposited La3Ga5O12, Gd3Ga5O12, Y3Fe5O12, and rf-magnetron sputtered Bi3Fe5O12 were chosen to host Er3+ ions on dodecahedral lattice sites. Er substituents with the concentration of 0.5 at. % (0.1 garnet formula units) do not decrease giant Faraday rotation in Bi2.9Er0.1Fe5O12 garnet; meanwhile providing intense room temperature C-band photoluminescence (PL). Fe3+ ion works as a sensitizer for Er resulting in fivefold PL enhancement in iron garnets compared to gallium ones. PL lifetime in gallium garnets is in millisecond range reaching almost 6 ms in Gd2.9Er0.1Ga5O12. We conclude Er substitution in gallium and iron garnet layers used both as Bragg mirrors and microcavities promises magneto-optical photonic crystals to become an active lasing medium.
Show PACS
78.66.Nk Insulators
78.55.Hx Other solid inorganic materials
78.20.Ls Magneto-optical effects
42.70.Qs Photonic bandgap materials
42.79.Bh Lenses, prisms and mirrors
42.79.Dj Gratings

Quantifying interlayer exchange coupling via layer-resolved hysteresis loops in antiferromagnetically coupled manganite/nickelate superlattices

Jihwey Park, Dong Ryeol Lee, Yongseong Choi, John W. Freeland, Ki Bong Lee, Sunil K. Sihna, K. R. Nikolaev, and Allen M. Goldman

Appl. Phys. Lett. 95, 102504 (2009); http://dx.doi.org/10.1063/1.3222944 (3 pages) | Cited 2 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In superlattices made of a half metallic ferromagnet La2/3Ba1/3MnO3(LBMO) and a metallic paramagnet LaNiO3(LNO), the field dependence of the LBMO magnetization was studied using depth- and element-sensitive x-ray resonant magnetic scattering measurements. The superlattices have ten bilayers of LBMO and LNO, and the LBMO layers were antiferromagnetically coupled across LNO spacer layers. From the x-ray measurements, the magnetic hysteresis loop of each LBMO layer was obtained, and subsequently the obtained layer-resolved LBMO hysteresis loops were utilized to determine the interlayer exchange coupling.
Show PACS
75.30.Et Exchange and superexchange interactions
75.20.Ck Nonmetals
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)

Microwave resonance in Fe/SiO2 nanocomposite

Ji Ma, Jiangong Li, Xia Ni, Xudong Zhang, and Juanjuan Huang

Appl. Phys. Lett. 95, 102505 (2009); http://dx.doi.org/10.1063/1.3224883 (3 pages) | Cited 16 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A broad resonance band in the 1–16 GHz range observed in Fe/SiO2 nanocomposite results from the coexsistence of natural resonance and exchange resonance. The natural resonance appears at 5.91 GHz and can be related to the core spins in the Fe nanoparticles, whereas the exchange resonance appears at 11.01 GHz and can be associated with the surface spins of the Fe nanoparticles in the Fe/SiO2 nanocomposite. Both resonance frequencies depend on the surface anisotropy of the Fe nanoparticles, which can be affected by the Fe particle size, and can be tuned by adjusting the Fe particle size.
Show PACS
78.70.Gq Microwave and radio-frequency interactions
75.50.Tt Fine-particle systems; nanocrystalline materials
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
75.30.Gw Magnetic anisotropy
75.30.Et Exchange and superexchange interactions

Defect-mediated room temperature ferromagnetism in vanadium dioxide thin films

Tsung-Han Yang, Sudhakar Nori, Honghui Zhou, and Jagdish Narayan

Appl. Phys. Lett. 95, 102506 (2009); http://dx.doi.org/10.1063/1.3224202 (3 pages) | Cited 12 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High quality epitaxial undoped vanadium oxide (VO2) thin films on c-plane sapphire (0001) substrate have been grown using pulsed laser deposition technique. The as-grown films exhibited excellent structural and transport properties without requiring further annealing treatments for these oxygen-deficient oxide films. The epitaxial growth has been achieved via domain matching epitaxy, where matching of integral multiples of planes occurs across the film-substrate interface. The magnetic properties of vanadium oxide (VO2) films investigated at different temperatures in the range of 10–360 K showed significant magnetic hysteresis as well as saturation of the magnetic moment. The origin of ferromagnetic properties with an estimated Curie temperature above 500 K is discussed in the absence of magnetic impurities in VO2 thin films as determined by x-ray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Dd Nonmetallic ferromagnetic materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
79.60.Dp Adsorbed layers and thin films
75.30.Hx Magnetic impurity interactions
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.30.Cr Saturation moments and magnetic susceptibilities

Experimental modeling of intergranular exchange coupling for perpendicular thin film media

Vincent Sokalski, David E. Laughlin, and Jian-Gang Zhu

Appl. Phys. Lett. 95, 102507 (2009); http://dx.doi.org/10.1063/1.3226638 (3 pages) | Cited 6 times

Online Publication Date: 11 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present an experimental model system that enables quantitative assessment of intergranular exchange coupling in CoCrPt-oxide perpendicular magnetic recording media. A thin film structure consisting of a high coercivity CoPt unicrystal layer and a lower coercivity CoPt layer separated by a thin oxide interlayer is used to model perpendicularly magnetized grains separated by oxide grain boundaries. Exchange coupling energy between the CoPt layers was obtained for SiOx, TiOx, and CrOx interlayers by measuring field shifts from the lower coercivity layer. Cr segregation in CoCrPt grains to grain boundaries is also modeled experimentally and found to significantly suppress exchange coupling.
Show PACS
75.30.Et Exchange and superexchange interactions
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Cc Other ferromagnetic metals and alloys
75.50.Ss Magnetic recording materials
75.50.Vv High coercivity materials
back to top
RSS Feeds

Combined electric field and stress-induced R-O phase transformation in [011]-poled Pb(Mg1/3Nb2/3)O3–(28–32)%PbTiO3 single crystals of [01math]-length cut

M. Shanthi and L. C. Lim

Appl. Phys. Lett. 95, 102901 (2009); http://dx.doi.org/10.1063/1.3222870 (3 pages) | Cited 7 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The combined effects of applied electric field and axial compressive stress on the strain behavior of [011]-poled Pb(Mg1/3Nb2/3)O3–(28–32)%PbTiO3 [PMN-(28–32)%PT] single crystals of [01math]-length cut have been investigated. For this crystal cut, the axial compressive stress has little effect on the R-O transformation field, the latter being >1.0 kV/mm for PMN-(28–30)%PT. This crystal cut is thus ideal for applications involving large electric field and axial compressive stress.
Show PACS
64.70.K- Solid-solid transitions
77.80.B- Phase transitions and Curie point
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.65.-j Piezoelectricity and electromechanical effects

Polarization retention of thin ferroelectricya capacitors

Youn Jung Park, Jiyoun Chang, Seok Ju Kang, and Cheolmin Park

Appl. Phys. Lett. 95, 102902 (2009); http://dx.doi.org/10.1063/1.3216053 (3 pages) | Cited 5 times

Online Publication Date: 9 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Excellent retention of the initial remanent polarizations was observed in ca. 200 nm thick ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) film capacitors with the writing pulse amplitude and time width of ±20 V and 1 ms, respectively, over 200 h at 80 °C. The opposite state program turned out more sensitive to retention deterioration than the same state one in both switching and nonswitching mode when either writing pulse amplitude or time width decreases. Nonswitching retention in the opposite state mode is in particular one of the most critical properties for designing a ferroelectric polymer capacitor memory.
Show PACS
84.32.Tt Capacitors
85.50.Gk Non-volatile ferroelectric memories

Unstable state in epitaxial films of sodium niobate

M. Tyunina and J. Levoska

Appl. Phys. Lett. 95, 102903 (2009); http://dx.doi.org/10.1063/1.3222900 (3 pages) | Cited 7 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxial perovskite-type films of sodium niobate were grown by pulsed laser deposition, and their crystal structure and dielectric properties were experimentally studied. The dielectric permittivity, inverse permittivity and its derivative, and dielectric hysteresis were analyzed and compared with those of antiferroelectric lead zirconate films. At temperatures in the interval of 80–600 K, the state of the sodium niobate films with relaxed misfit strain is interpreted as an unstable coexistence of antiferroelectric and ferroelectric phases. The origin of the ferroelectric phase is discussed.
Show PACS
77.80.Dj Domain structure; hysteresis
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.15.Fg Pulsed laser ablation deposition
77.22.Ch Permittivity (dielectric function)
68.55.-a Thin film structure and morphology

Enhanced piezoelectric and ferroelectric properties in Mn-doped Na0.5Bi0.5TiO3–BaTiO3 single crystals

Qinhui Zhang, Yaoyao Zhang, Feifei Wang, Yaojin Wang, Di Lin, Xiangyong Zhao, Haosu Luo, Wenwei Ge, and D. Viehland

Appl. Phys. Lett. 95, 102904 (2009); http://dx.doi.org/10.1063/1.3222942 (3 pages) | Cited 33 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High piezoelectric and ferroelectric properties have been found in Mn-doped Na0.5Bi0.5TiO3–BaTiO3 single crystals, which were grown by a top-seeded solution method. The electrical resistivity, dielectric constant, and ferroelectric and piezoelectric properties were all found to be notably enhanced by Mn. The piezoelectric constant d33 and electromechanical coupling coefficients kt and k31 were found to be as high as 483 pC/N, 0.56, and 0.40, respectively. These values are much higher than those previously reported for Pb-free piezoelectric crystals, demonstrating the real potential for alternative lead-free systems for sensor and piezoelectric applications.
Show PACS
77.65.Bn Piezoelectric and electrostrictive constants
72.80.Sk Insulators
77.80.Fm Switching phenomena
77.22.Ch Permittivity (dielectric function)
81.10.Dn Growth from solutions
77.22.Ej Polarization and depolarization
77.80.B- Phase transitions and Curie point

Density functional calculations on atomic and electronic structures of amorphous HfO2/Si(001) interface

G. H. Chen, Z. F. Hou, and X. G. Gong

Appl. Phys. Lett. 95, 102905 (2009); http://dx.doi.org/10.1063/1.3226636 (3 pages) | Cited 2 times

Online Publication Date: 10 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The interface properties of amorphous hafnium dioxide (a-HfO2) in contact with silicon have been investigated by using the projector augmented wave method within the generalized gradient approximation. The a-HfO2 model structure of the interface is generated by ab initio molecular dynamics simulations in a melt-and-quench scheme. Calculations indicate that the simulated a-HfO2 essentially shows the characteristics of the experimental a-HfO2 structure. The results on a-HfO2/Si interface suggest that atomic coordination of interface Si atoms would significantly affect the interface electronic properties, e.g., the Hf–Si bond formed at the interface could result in metallic behavior. With band lineup of the core level, the valence band offset of a-HfO2/Si interface is determined to be 2.62±0.35 eV, in good agreement with recent experimental data.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
61.66.Fn Inorganic compounds
73.20.-r Electron states at surfaces and interfaces
61.50.Lt Crystal binding; cohesive energy
71.15.Pd Molecular dynamics calculations (Car-Parrinello) and other numerical simulations
back to top
RSS Feeds

Higher-order surface free energy in azimuthal nematic anchoring on nanopatterned grooves

Jin Seog Gwag, Jin Hyuk Kwon, Masahito Oh-e, Jun-ichi Niitsuma, Makoto Yoneya, and Hiroshi Yokoyama

Appl. Phys. Lett. 95, 103101 (2009); http://dx.doi.org/10.1063/1.3225556 (3 pages) | Cited 5 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The higher-order component in liquid crystal (LC) surface free energy beyond the Rapini–Papoular anchoring potential was examined for azimuthal anchoring by analyzing nematic LC alignment on nanogrooved surfaces treated by rubbing or photoalignment. We confirmed that the surface anchoring energy for large director deviations cannot be properly described with the Rapini–Papoular form and should include higher order contributions in a power series of sin2 ϕ, as ∑n = 12Wn sin2n ϕ, with ϕ being the azimuthal angular deviation. Based on the corrected Berreman’s theory, we obtained the anchoring ratio between the first and second order terms, W2/W1 ≈ −1/4, and the surface elastic constant, K24 ≈ −0.846K22, for 4-n-pentyl-4′-cyanobiphenyl.
Show PACS
61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions
68.03.Cd Surface tension and related phenomena
65.20.Jk Studies of thermodynamic properties of specific liquids
62.10.+s Mechanical properties of liquids
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials

Design and performance of a simple, room-temperature Ga2O3 nanowire gas sensor

S. P. Arnold, S. M. Prokes, F. K. Perkins, and M. E. Zaghloul

Appl. Phys. Lett. 95, 103102 (2009); http://dx.doi.org/10.1063/1.3223617 (3 pages) | Cited 10 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ga2O3 nanowire gas sensors were fabricated using the vapor-liquid-solid method of nanowire growth over platinum interdigitated electrodes. While cheaply and easily fabricated, the sensors are capable of detecting various analytes at room temperature. As analyte is adsorbed onto the nanowire surfaces, a change in the device capacitance is measured. Fast recovery of the sensing devices, without the use of an external heat source, allows these devices to operate at low power. Capacitance is seen to increase following a Freundlich isotherm in response to increasing concentrations of analyte vapors.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
82.80.-d Chemical analysis and related physical methods of analysis
81.16.-c Methods of micro- and nanofabrication and processing
68.43.Fg Adsorbate structure (binding sites, geometry)
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Semiconductor behaviors of low loading multiwall carbon nanotube/poly(dimethylsiloxane) composites

C. H. Hu, C. H. Liu, L. Z. Chen, and S. S. Fan

Appl. Phys. Lett. 95, 103103 (2009); http://dx.doi.org/10.1063/1.3223777 (3 pages) | Cited 3 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a flexible electronic material fabricated by incorporating multiwall carbon nanotubes (MWNTs) into poly(dimethylsiloxane) rubber (0.35 wt % MWNT loading is most appropriate in our study). Resistance-temperature data for different composites (0.35–5 wt %) are analyzed within Coulomb gap variable range hopping model, which well explains the semiconductor behaviors in low MWNT loading composites. Field effect transistors fabricated using 0.35 wt % composite show a p-type behavior with a high effective mobility of 1.98 cm2 V s and linear transconductance 8.34×10−8 S at 2.5 V drain voltage. These results suggest an optional way of seeking for high-quality flexible electronic materials.
Show PACS
81.05.Qk Reinforced polymers and polymer-based composites
81.07.De Nanotubes
85.30.Tv Field effect devices

Transparent self-assembled films of reduced graphene oxide platelets

Yanwu Zhu, Weiwei Cai, Richard D. Piner, Aruna Velamakanni, and Rodney S. Ruoff

Appl. Phys. Lett. 95, 103104 (2009); http://dx.doi.org/10.1063/1.3212862 (3 pages) | Cited 35 times

Online Publication Date: 8 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Transparent conducting films have been fabricated in one step, combining self-assembly and chemical reduction of graphene oxide platelets dispersed in water. The films are of centimeter scale and their thickness can be controlled by the concentration of the graphene oxide suspension. The optical transmittance values at a wavelength of 550 nm were 87% and 96% for the films made from 1.5 and 0.5 mg/ml suspensions, respectively, and have sheet resistances of 11.3 and 31.7 kΩ/◻. Scanning and transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy were used to characterize the films.
Show PACS
81.16.Dn Self-assembly
68.60.-p Physical properties of thin films, nonelectronic
79.60.Dp Adsorbed layers and thin films
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Nk Insulators
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close