APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

23 Jan 2012

Volume 100, Issue 4, Articles (04xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 041101 (2012); http://dx.doi.org/10.1063/1.3675885 (4 pages)

Seung Ho Choi and Young L. Kim
Enlarge Image | Read More
Page 3 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Origin of the enhanced polarization in La and Mg co-substituted BiFeO3 thin film during the fatigue process

Qingqing Ke, Amit Kumar, Xiaojie Lou, Kaiyang Zeng, and John Wang

Appl. Phys. Lett. 100, 042902 (2012); http://dx.doi.org/10.1063/1.3678636 (4 pages) | Cited 4 times

Online Publication Date: 25 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the polarization fatigue of La and Mg co-substituted BiFeO3 thin film, where a polarization peak is observed during the fatigue process. The origin of such anomalous behavior is analyzed on the basis of the defect evolution using temperature-dependent impedance spectroscopy. It shows that the motion of oxygen vacancies (VO••) is associated with a lower energy barrier, accompanied by the injection of electrons into the film during the fatigue process. A qualitative model is proposed to explain the fatigue behavior, which involves the modification of the Schottky barrier upon the accumulation of VO•• at the metal-dielectric interface.
Show PACS
77.22.Ej Polarization and depolarization
77.80.Fm Switching phenomena
61.72.jd Vacancies
77.55.Nv Multiferroic/magnetoelectric films
77.55.fp Other ferroelectric films
FREE

Giant electro-mechanical energy conversion in [011] cut ferroelectric single crystals

Wen D. Dong, Peter Finkel, Ahmed Amin, and Christopher S. Lynch

Appl. Phys. Lett. 100, 042903 (2012); http://dx.doi.org/10.1063/1.3679644 (3 pages) | Cited 4 times

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Giant electro-mechanical energy conversion is demonstrated under a ferroelectric/ferroelectric phase transformation in [011] cut and poled lead titanate-based relaxor perovskite morphotropic single crystals. It is found that under mechanical pre-stress, a relatively small oscillatory stress drives the material reversibly between rhombohedral and orthorhombic phases with a remarkably high polarization and strain jump induced at zero bias electric field and room temperature. The measured electrical output per cycle is more than an order of magnitude larger than that reported for linear piezoelectric materials. Ideal thermodynamic cycles are presented for this electro-mechanical energy conversion followed by a presentation and discussion of the experimental data.
Show PACS
77.80.B- Phase transitions and Curie point
77.80.Jk Relaxor ferroelectrics
77.84.Cg PZT ceramics and other titanates
77.22.Ej Polarization and depolarization

Relaxor ferroelectric behavior of BaMnO3 (2H) at room temperature

S. Satapathy, M. K. Singh, Pragya Pandit, and P. K. Gupta

Appl. Phys. Lett. 100, 042904 (2012); http://dx.doi.org/10.1063/1.3679176 (4 pages)

Online Publication Date: 27 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Geometrically frustrated hexagonal BaMnO3 (2H) is an interesting material due to the presence of more than one ferroic order parameters. Although the material is well known, still there exists confusion on the crystal structure of this material at room temperature and its ferroelectric properties have not been explored. Here, we report noncentrosymmetric crystal structure and ferroelectric properties of BaMnO3 (2H) at room temperature. The dielectric diffusivity calculated from modified Curie-Weiss laws and non linear Vogel-Fulcher fittings implies weak relaxor characteristic of BaMnO3 (2H). The ferroelectric properties arise due to off centering of Mn4+ ion in unit cell and weak relaxor properties are attributed to the presence of a smaller amount of Mn3+ cations which creates disorder in 2H-BaMnO3.
Show PACS
77.80.Jk Relaxor ferroelectrics
61.66.Fn Inorganic compounds
77.22.Ch Permittivity (dielectric function)
77.80.Dj Domain structure; hysteresis
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
back to top
RSS Feeds

Plasmonic light trapping leads to responsivity increase in colloidal quantum dot photodetectors

F. Pelayo García de Arquer, Fiona J. Beck, María Bernechea, and Gerasimos Konstantatos

Appl. Phys. Lett. 100, 043101 (2012); http://dx.doi.org/10.1063/1.3678039 (4 pages) | Cited 4 times

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report broadband responsivity enhancement in PbS colloidal quantum dot (CQDs) photoconductive photodetectors due to absorption increase offered by a plasmonic scattering layer of Ag metal nanoparticles. Responsivity enhancements are observed in the near infrared with a maximum 2.4-fold increase near the absorption band edge of ∼1 μm for ∼400 nm thick devices. Additionally, we study the effect of the mode structure on the efficiency of light trapping provided by random nanoparticle scattering in CQD films and provide insights for plasmonic scattering enhancement in CQD thin films.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
Author Select

Transforming graphite to nanoscale diamonds by a femtosecond laser pulse

R. Nüske, A. Jurgilaitis, H. Enquist, M. Harb, Y. Fang, U. Håkanson, and J. Larsson

Appl. Phys. Lett. 100, 043102 (2012); http://dx.doi.org/10.1063/1.3678190 (4 pages) | Cited 1 time

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Formation of cubic diamond from graphite following irradiation by a single, intense, ultra-short laser pulse has been observed. Highly oriented pyrolytic graphite (HOPG) samples were irradiated by a 100 fs pulse with a center wavelength of 800 nm. Following laser exposure, the HOPG samples were studied using Raman spectroscopy of the sample surface. In the laser-irradiated areas, nanoscale cubic diamond crystals have been formed. The exposed areas were also studied using grazing incidence x-ray powder diffraction showing a restacking of planes from hexagonal graphite to rhombohedral graphite.
Show PACS
64.70.K- Solid-solid transitions
61.46.Bc Structure of clusters (e.g., metcars; not fragments of crystals; free or loosely aggregated or loosely attached to a substrate)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
64.70.Nd Structural transitions in nanoscale materials
78.30.Na Fullerenes and related materials

Metal-insulator transition sustained by Cr-doping in V2O3 nanocrystals

Yoichi Ishiwata, Tatsuya Shiraishi, Naoki Ito, Satoshi Suehiro, Tetsuya Kida, Hirofumi Ishii, Yasuhisa Tezuka, Yuji Inagaki, Tatsuya Kawae, Hirotaka Oosato, Eiichiro Watanabe, Daiju Tsuya, Masashi Nantoh, and Koji Ishibashi

Appl. Phys. Lett. 100, 043103 (2012); http://dx.doi.org/10.1063/1.3679396 (3 pages) | Cited 2 times

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have obtained monodisperse (V1−xCrx)2O3 nanocrystals with crystal sizes of 21.0 ± 4.1 nm using organic-phase synthesis. The (V1−xCrx)2O3 nanocrystals clearly show the transition from a corundum structured paramagnetic metal to a monoclinic structured antiferromagnetic insulator in contrast to non-doped V2O3 nanocrystals, in which the disappearance of the metal-insulator transition has been observed. We have found that Cr doping works effectively in narrowing the a1g band, which tends to be broadened by nanocrystallization. This result suggests that chemical doping is useful for control of material phase transitions at the nanoscale.
Show PACS
81.07.Bc Nanocrystalline materials
61.72.up Other materials
64.70.dg Crystallization of specific substances
64.70.Nd Structural transitions in nanoscale materials
71.30.+h Metal-insulator transitions and other electronic transitions
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Improved electron field emission from morphologically disordered monolayer graphene

Srikrishna Pandey, Padmnabh Rai, Shashikant Patole, Fethullah Gunes, Gi-Duk Kwon, Ji-Beom Yoo, Pavel Nikolaev, and Sivaram Arepalli

Appl. Phys. Lett. 100, 043104 (2012); http://dx.doi.org/10.1063/1.3679135 (4 pages) | Cited 3 times

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Graphene was synthesized on copper foil by thermal chemical vapor deposition technique. To investigate the field electron emission property, planar graphene (PG) and morphologically disordered graphene (MDG) were fabricated on the doped silicon substrate by transfer of as-grown graphene. Incorporation of morphological disorder in graphene creates more emission sites due to the additional defects, edges, and atomic scale ripples. This resulted in (1) a dramatic increase in the maximum current density by a factor of 500, (2) considerable increase in the enhancement factor, and (3) decrease in the turn-on field of MDG compared to PG.
Show PACS
81.05.ue Graphene
79.70.+q Field emission, ionization, evaporation, and desorption
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.48.Gh Structure of graphene

Nano-hole array structure with improved surface plasmon energy matching characteristics

Mohamadreza Najiminaini, Fartash Vasefi, Bozena Kaminska, and Jeffrey J. L. Carson

Appl. Phys. Lett. 100, 043105 (2012); http://dx.doi.org/10.1063/1.3679173 (4 pages) | Cited 4 times

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a nano-hole array structure in an opaque gold film that contains a cavity beneath each nano-hole. The cavity contributes to surface plasmon energy matching between the top and bottom surfaces of the gold and within the nano-hole structures. Based on bulk surface plasmon resonance (SPR) sensing experiments, the SP-matched structure had 2.8-fold higher differential transmission, 2-fold higher sensitivity, and a 7-fold higher ratio of extraordinary optical transmission at resonance to the nearby minimum compared to a conventional NHA. The results suggest that the structure with cavities has potential to improve performance of bulk SPR sensing applications.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

High magnetic field annealing effect on visible photoluminescence enhancement of TiO2 nanotube arrays

Mingjie Yang, Wei Liu, Jia-Lin Sun, and Jia-Lin Zhu

Appl. Phys. Lett. 100, 043106 (2012); http://dx.doi.org/10.1063/1.3679621 (4 pages)

Online Publication Date: 25 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
TiO2 nanotube arrays with remarkable visible photoluminescence were prepared by high magnetic field annealing in air at 450 °C due to the involvement of oxygen vacancies (OVs). A field with the intensities of 0, 2, 4, 6, and 8 T were applied in the annealing processing, along the directions set at 0°, 50°, and 90° from the surface normal of the substrate. The results demonstrated that the density of oxygen vacancies in TiO2 nanotubes can be controlled by varying the intensity and direction of the magnetic field. The mechanism for the effect of the high magnetic field has been investigated. This study opens an effective way to control the oxygen vacancies in nanomaterials to improve their performance.
Show PACS
75.60.Nt Magnetic annealing and temperature-hysteresis effects
78.20.Ls Magneto-optical effects
78.55.Hx Other solid inorganic materials
78.67.Ch Nanotubes
81.16.-c Methods of micro- and nanofabrication and processing

Effective energy gap of the double-walled carbon nanotubes with field effect transistors ambipolar characteristics

Takahiro Morimoto, Akihiro Kuno, Shota Yajima, Koji Ishibashi, Koji Tsuchiya, and Hirofumi Yajima

Appl. Phys. Lett. 100, 043107 (2012); http://dx.doi.org/10.1063/1.3679639 (3 pages) | Cited 1 time

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the transport property of the double-walled carbon nanotubes (DWCNT)-field effect transistor (FET) devices with HfO2 insulating layers at room temperature and 4.2 K. These devices show the ambipolar FET characteristics after deposition of HfO2 insulating layer. The off-regions of ambipolar behavior have clear dependence on their DWCNT diameter. The conversion factor of gate voltages and bias voltages is estimated from low temperature Coulomb Diamond measurement. Using same device structure and dimensions to all devices, these off-regions of threshold voltage are converted to effective energy gap. These energy gaps are in good agreement with theoretical predictions.
Show PACS
85.35.Kt Nanotube devices

Plasmon assisted light propagation and Raman scattering hot-spot in end-to-end coupled silver nanowire pairs

Rohit Chikkaraddy, Danveer Singh, and G. V. Pavan Kumar

Appl. Phys. Lett. 100, 043108 (2012); http://dx.doi.org/10.1063/1.3679649 (3 pages) | Cited 4 times

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Herein, we report on the experimental observation of light propagation and localization capabilities of end-to-end connected silver nanowire (Ag NW) pairs. By exciting the surface plasmon polaritons at one end of Ag NW pair, we observed relatively intense light emission at the junction and weak light emission at the distal end of the pair. To probe the localization of light at nanowire junction, we captured far-field Raman image of an isolated Ag NW pair adsorbed with rhodamine 6 G and observed enhanced Raman scattering at the nanowire junction. Such nanophotonic modules with light propagation and localization capabilities can be harnessed for multiplexed on-chip plasmonics.
Show PACS
73.22.Lp Collective excitations
78.30.Er Solid metals and alloys
68.43.Mn Adsorption kinetics
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Anomalous electron transport in back-gated field-effect transistors with TiTe2 semimetal thin-film channels

J. Khan, C. M. Nolen, D. Teweldebrhan, D. Wickramaratne, R. K. Lake, and A. A. Balandin

Appl. Phys. Lett. 100, 043109 (2012); http://dx.doi.org/10.1063/1.3679679 (4 pages) | Cited 9 times

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on “graphene-like” mechanical exfoliation of thin films of titanium ditelluride and investigation of their electronic properties. The exfoliated crystalline TiTe2 films were used as the channel layers in the back-gated field-effect transistors fabricated with Ti/Al/Au metal contacts on SiO2/Si substrates. The room-temperature current-voltage characteristics revealed strongly non-linear behavior with signatures of the source-drain threshold voltage similar to those observed in the charge-density-wave devices. The drain-current showed an unusual non-monotonic dependence on the gate bias characterized by the presence of multiple peaks. The obtained results can be potentially used for implementation of the non-Boolean logic gates.
Show PACS
85.75.Hh Spin polarized field effect transistors
68.55.-a Thin film structure and morphology
73.61.-r Electrical properties of specific thin films

Side-dependent electron escape from graphene- and graphane-like SiC layers

Paola Gori, Olivia Pulci, Margherita Marsili, and Friedhelm Bechstedt

Appl. Phys. Lett. 100, 043110 (2012); http://dx.doi.org/10.1063/1.3679175 (4 pages) | Cited 3 times

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structural and electronic properties of SiC-based two-dimensional (2D) crystals are studied by means of density functional theory and many-body perturbation theory. Such properties cannot simply be interpolated between graphene and silicene. The replacement of half of the C atoms by Si atoms opens a large direct electronic gap and destroys the Dirac cones. Hydrogenation further opens the gap and significantly reduces the electron affinity to 0.1 or 1.8 eV in dependence on the carbon or silicon termination of the 2D crystal surface, thus showing a unique direction dependent ionization potential. This suggests the use of 2D-SiC:H as electron or hole filter.
Show PACS
73.22.Pr Electronic structure of graphene
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
73.61.Wp Fullerenes and related materials
61.48.Gh Structure of graphene
68.65.Pq Graphene films
back to top
RSS Feeds
FREE

Micro-imprinted prism substrate for self-aligned short channel organic transistors on a flexible substrate

Jin Jeon, Benjamin C.-K. Tee, Boris Murmann, and Zhenan Bao

Appl. Phys. Lett. 100, 043301 (2012); http://dx.doi.org/10.1063/1.3679119 (4 pages) | Cited 4 times

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using a simple micro-imprinting process on flexible substrates, we demonstrate fabrication of self-aligned short channel organic thin film transistors (OTFTs) with significantly reduced parasitic capacitance. The surface topology resulting from the imprinted prism-like structures enables accurate alignment of both the gate and source-drain electrodes. The parasitic overlap capacitance was reduced by 80%, which enables twice higher transition frequency (fT = 10.1 kHz) compared with conventional top-contact OTFT devices. The prism-OTFTs were applied to both p-type (pentacene) and n-type (C60) organic semiconductors to implement low voltage complementary inverters.
Show PACS
85.30.Tv Field effect devices
FREE

Enhanced carrier injection in pentacene thin-film transistors by inserting a MoO3-doped pentacene layer

Zhaokui Wang, Mir Waqas Alam, Yanhui Lou, Shigeki Naka, and Hiroyuki Okada

Appl. Phys. Lett. 100, 043302 (2012); http://dx.doi.org/10.1063/1.3680249 (4 pages) | Cited 6 times

Online Publication Date: 27 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the enhanced carrier injection in pentacene thin-film transistors with a thin MoO3-doped pentacene layer between pentacene semiconductor and the source-drain electrodes. Device performance including drain current, field effect mobility, and threshed voltage are improved by employing a MoO3-doped pentacene thin layer. The barrier height at the Au/pentacene interface is lowered from 0.12 to 0.05 eV after inserting a MoO3-doped pentacene thin layer between them. The reduced barrier height is attributed to the formation of a good contact between MoO3-doped pentacene and Au owing to smoothed surface morphology of pentancene and suitable band bending by MoO3 doping.
Show PACS
85.30.Tv Field effect devices
back to top
RSS Feeds

Cholesteric liquid crystal-carbon nanotube hybrid architectures for gas detection

Chin-Kai Chang, Shih-Wen Chiu, Hui-Lung Kuo, and Kea-Tiong Tang

Appl. Phys. Lett. 100, 043501 (2012); http://dx.doi.org/10.1063/1.3679680 (3 pages) | Cited 5 times

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The ability of a hybrid material that is based on cholesteric liquid crystal and carbon nanotube to detect acetone vapor is investigated. We find that the phase transition in this cholesteric liquid crystal-carbon nanotube hybrid will enable carbon nanotube to form conducting networks under the higher vapor concentration. This cholesteric liquid crystal-carbon nanotube hybrid exhibits an obvious change in reflected color and electrical resistance in the early and later stages of gas diffusion, respectively. This hybrid architecture has potential application as a gas sensor with a high dynamic range.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
73.61.Wp Fullerenes and related materials

Time-resolved photocurrents in quantum well/dot infrared photodetectors with different optical coupling structures

Zhi-Hui Chen, S. Hellström, Zhong-Yuan Yu, Min Qiu, and Y. Fu

Appl. Phys. Lett. 100, 043502 (2012); http://dx.doi.org/10.1063/1.3678637 (5 pages)

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Temporal developments of photocurrents excited by an infrared radiation pulse in quantum well/dot infrared photodetectors with different optical coupling structures have been theoretically studied. It is shown that the light diffraction in a conventional reflective grating structure is a near-field effect containing severe crosstalk from neighboring pixels. A concave reflector not only eliminates the crosstalk but also strongly diffracts and focuses the incident electric field into deep active layers, which significantly increases the photocurrents in the photodetectors.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
78.67.De Quantum wells
78.67.Hc Quantum dots
85.60.Gz Photodetectors (including infrared and CCD detectors)

Effect of channel widths on negative shift of threshold voltage, including stress-induced hump phenomenon in InGaZnO thin-film transistors under high-gate and drain bias stress

Sung-Hwan Choi and Min-Koo Han

Appl. Phys. Lett. 100, 043503 (2012); http://dx.doi.org/10.1063/1.3679109 (3 pages) | Cited 4 times

Online Publication Date: 23 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated the degradation of indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) for various channel widths under high-gate and drain bias stress. The threshold voltage of IGZO TFT with wide-channel width (W > 100 μm) was significantly shifted. This included stress-induced hump-effect in a negative direction after the stress, whereas IGZO TFT with narrow-channel width (W < 100 μm) shifted in a positive direction. This phenomenon may be attributed to the hole trapping into the back-interface region. In order to enhance the reliability of IGZO TFTs, we developed and verified that the multiple-channel device showed better bias-temperature stability (ΔVTH: −0.1 V), whereas the single-channel device exhibited a −0.4 VΔVTH shift.
Show PACS
85.30.Tv Field effect devices

Vertical waveguides integrated with silicon photodetectors: Towards high efficiency and low cross-talk image sensors

Turgut Tut, Yaping Dan, Peter Duane, Young Yu, Munib Wober, and Kenneth B. Crozier

Appl. Phys. Lett. 100, 043504 (2012); http://dx.doi.org/10.1063/1.3678019 (3 pages)

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe the experimental realization of vertical silicon nitride waveguides integrated with silicon photodetectors. The waveguides are embedded in a silicon dioxide layer. Scanning photocurrent microscopy is performed on a device containing a waveguide, and on a device containing the silicon dioxide layer, but without the waveguide. The results confirm the waveguide’s ability to guide light onto the photodetector with high efficiency. We anticipate that the use of these structures in image sensors, with one waveguide per pixel, would greatly improve efficiency and significantly reduce inter-pixel crosstalk.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.79.Gn Optical waveguides and couplers

Ceasing of voltage switching amongst graphitic shells in multiwalled carbon nanotubes: A route toward stability

Neha Kulshrestha, Abhishek Misra, Reeti Bajpai, Soumyendu Roy, and D. S. Misra

Appl. Phys. Lett. 100, 043505 (2012); http://dx.doi.org/10.1063/1.3679397 (4 pages)

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Weakly interacting graphitic shells of different resistivities within multiwalled carbon nanotubes (MWNTs) cause instability in current and thus limit their reliability for electronic device applications. We here demonstrate voltage switching amongst graphitic shells of MWNTs by applying current sweeps with observed switching time in the range of 100–400 ms. We further demonstrate ceasing of this switching behaviour by local metal deposition on the MWNTs. After metal deposition, the graphitic shells behave like resistive wires connected altogether. This concept of metal deposition benefits in the higher conductivity and stable currents for MWNTs and proves their strong candidature as interconnecting wires.
Show PACS
81.05.U- Carbon/carbon-based materials
72.60.+g Mixed conductivity and conductivity transitions
73.63.Fg Nanotubes
81.07.De Nanotubes

Large anisotropic remnant magnetization tunability in (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 multiferroic epitaxial heterostructures

Yuanjun Yang, Meng Meng Yang, Z. L. Luo, Haoliang Huang, Haibo Wang, J. Bao, Chuansheng Hu, Guoqiang Pan, Yiping Yao, Yukuai Liu, X. G. Li, Sen Zhang, Y. G. Zhao, and C. Gao

Appl. Phys. Lett. 100, 043506 (2012); http://dx.doi.org/10.1063/1.3676044 (3 pages) | Cited 3 times

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A large anisotropic remnant magnetization tunability was observed in multiferroic (011)-La2/3Sr1/3MnO3/0.7Pb(Mg2/3Nb1/3)O3-0.3PbTiO3 (LSMO/PMN-0.3PT) epitaxial heterostructures. The remnant magnetization along [100] direction was suppressed by an electric field applied to the substrate while the remnant magnetization along [01math] was enhanced. The tunabilities of the remnant magnetization along the [100] and [01math] directions are about −17.9% and +157% under electric field of +7.27 kV/cm, respectively. This large anisotropic remnant magnetization tunability may find potential applications in the electrically written and magnetically read memories.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.70.Ak Magnetic properties of monolayers and thin films
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.85.+t Magnetoelectric effects, multiferroics
75.30.Gw Magnetic anisotropy

A Monte Carlo study of the low resistance state retention of HfOx based resistive switching memory

Shimeng Yu, Yang Yin Chen, Ximeng Guan, H.-S. Philip Wong, and Jorge A. Kittl

Appl. Phys. Lett. 100, 043507 (2012); http://dx.doi.org/10.1063/1.3679610 (4 pages) | Cited 5 times

Online Publication Date: 24 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A Monte Carlo simulator is developed to investigate the low resistance state (LRS) retention of HfOx based resistive switching memory. The simulator tracks the evolution of oxygen ions and oxygen vacancies by choosing the occurrence of the generation/recombination/migration processes based on their corresponding probability at each simulation step. The current through the resulting conductive filament (CF) configuration is then calculated by a trap-assisted-tunneling solver. The simulation results are corroborated with experimental data. The LRS retention is found to be CF size dependent, and its variability is suggested to be intrinsic due to the stochastic nature of the CF dissolution. The tail bits of the failure time distribution become a limiting factor of the device reliability in a large memory array.
Show PACS
84.30.Sk Pulse and digital circuits

Single charge sensing and transport in double quantum dots fabricated from commercially grown Si/SiGe heterostructures

C. Payette, K. Wang, P. J. Koppinen, Y. Dovzhenko, J. C. Sturm, and J. R. Petta

Appl. Phys. Lett. 100, 043508 (2012); http://dx.doi.org/10.1063/1.3678043 (3 pages) | Cited 3 times

Online Publication Date: 25 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We perform quantum Hall measurements on three types of commercially available modulation-doped Si/SiGe heterostructures to determine their suitability for depletion gate defined quantum dot devices. By adjusting the growth parameters, we are able to achieve electron gases with charge densities 1–3 × 1011/cm2 and mobilities in excess of 100 000 cm2/Vs. Double quantum dot devices fabricated on these heterostructures show clear evidence of single charge transitions as measured in dc transport and charge sensing and exhibit electron temperatures of 100 mK in the single quantum dot regime.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.43.-f Quantum Hall effects
72.20.Fr Low-field transport and mobility; piezoresistance
73.21.La Quantum dots

The influence of Al composition on point defect incorporation in AlGaN

T. A. Henry, A. Armstrong, A. A. Allerman, and M. H. Crawford

Appl. Phys. Lett. 100, 043509 (2012); http://dx.doi.org/10.1063/1.3679681 (4 pages) | Cited 1 time

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of point defects in AlxGa1−xN (x = 0-0.33) films with similar threading dislocation densities were investigated. The epitaxial layers were grown under conditions applicable to laser-diode quantum wells, barriers and waveguide layers. The evolution of deep level defect energy and density were quantitatively tracked versus x using deep level optical spectroscopy. Three defect levels were observed, whose defect density increased with x. The energy level of a defect suspected to be related to the group-III vacancy appeared to track the vacuum level, and a near-valence band defect level deepened with respect to the valence band maximum.
Show PACS
71.55.Eq III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.jd Vacancies
68.55.ag Semiconductors
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
71.20.Nr Semiconductor compounds

Spin transport in memristive devices

Hyuk-Jae Jang, Oleg A. Kirillov, Oana D. Jurchescu, and Curt A. Richter

Appl. Phys. Lett. 100, 043510 (2012); http://dx.doi.org/10.1063/1.3679114 (4 pages) | Cited 2 times

Online Publication Date: 26 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on electron spin transport through electrochemically precipitated copper filaments formed in TaOx memristive devices consisting of Co/TaOx/Cu/Py with crossbar-type electrode geometry. The devices show memristive behavior having a typical OFF/ON resistance ratio of 105. Magnetoresistance measurements performed by sweeping an external magnetic field clearly indicate spin transport through an electrochemically formed copper nano-filament as long as 16 nm in the memristive ON-state at 77 K. Spin transport vanishes in the OFF-state. These data are strong evidence that the fundamental switching mechanism in these metal-oxide devices is the formation of continuous metallic conduction paths.
Show PACS
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)
85.35.-p Nanoelectronic devices
85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
Page 3 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close