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1.
Yanming Sun Yunqi Liu Ying Wang Chongan Di Weiping Wu Gui Yu 《Applied Physics A: Materials Science & Processing》2009,95(3):777-780
Organic thin-film transistors based on polycrystalline copper phthalocyanine (CuPc) were fabricated by using poly(vinyl alcohol)
as gate dielectric. After treatment of the gate dielectric using an octadecyltrichlorosilane self-assembled monolayer, a mobility
of up to 0.11 cm2/V s was achieved, which is comparable to that of single-crystal CuPc devices (0.1–1 cm2/V s). The surface morphology was analyzed and the possible reasons for the enhanced mobility are discussed. 相似文献
2.
Wang Bin Zhao Yue Min Jiahua Sang Wenbin 《Applied Physics A: Materials Science & Processing》2009,94(4):715-718
P-type ZnO was realized by dual-doping with nitrogen and silver via electrostatic-enhanced ultrasonic spray pyrolysis. The
structural, electrical, and optical properties were explored by XRD, Hall-effect, and optical transmission spectra. The resistivity
of ZnO:(N,Ag) film was found to be 56 Ω cm−1 with the high mobility of 76.1 cm2/V s. Compared with ZnO:Ag film, ZnO:(N,Ag) film exhibited a higher and more stable optical transmittance. 相似文献
3.
H. Kim A. Cepler C. Cetina D. Knies M. S. Osofsky R. C. Y. Auyeung A. Piqué 《Applied Physics A: Materials Science & Processing》2008,93(3):593-598
Present p-type ZnO films tend to exhibit high resistivity and low carrier concentration, and they revert to their natural n-type state
within days after deposition. One approach to grow higher quality p-type ZnO is by codoping the ZnO during growth. This article describes recent results from the growth and characterization
of Zr–N codoped p-type ZnO thin films by pulsed laser deposition (PLD) on (0001) sapphire substrates. For this work, both N-doped and Zr–N
codoped p-type ZnO films were grown for comparison purposes at substrate temperatures ranging between 400 to 700 °C and N2O background pressures between 10−5 to 10−2 Torr. The carrier type and conduction were found to be very sensitive to substrate temperature and N2O deposition pressure. P-type conduction was observed for films grown at pressures between 10−3 to 10−2 Torr. The Zr–N codoped ZnO films grown at 550 °C in 1×10−3 Torr of N2O show p-type conduction behavior with a very low resistivity of 0.89 Ω-cm, a carrier concentration of 5.0×1018 cm−3, and a Hall mobility of 1.4 cm2 V−1 s−1. The structure, morphology and optical properties were also evaluated for both N-doped and Zr–N codoped ZnO films. 相似文献
4.
Zhaoyue Lü Zhenbo Deng Jianjie Zheng Ye Zou Zheng Chen Denghui Xu Yongsheng Wang 《Physica E: Low-dimensional Systems and Nanostructures》2009,41(10):1806-1809
The effect of indium-tin oxide (ITO) surface treatment on hole injection of devices with molybdenum oxide (MoO3) as a buffer layer on ITO was studied. The Ohmic contact is formed at the metal/organic interface due to high work function of MoO3. Hence, the current is due to space charge limited when ITO is positively biased. The hole mobility of N, N′-bis-(1-napthyl)-N, N′-diphenyl-1, 1′biphenyl-4, 4′-diamine (NPB) at various thicknesses (100–400 nm) has been estimated by using space-charge-limited current measurements. The hole mobility of NPB, 1.09×10−5 cm2/V s at 100 nm is smaller than the value of 1.52×10−4 cm2/V s at 400 nm at 0.8 MV/cm, which is caused by the interfacial trap states restricted by the surface interaction. The mobility is hardly changed with NPB thickness for the effect of interfacial trap states on mobility which can be negligible when the thickness is more than 300 nm. 相似文献
5.
The reactive ion beam mixing (IBM) of V/Al interfaces by low-energy N2+ ions at room temperature leads to the formation of V–Al–N ternary nitride thin films. The kinetics, growth mechanisms, composition
and electronic structure of those films have been studied using X-ray photoelectron spectroscopy, ultraviolet photoelectron
spectroscopy, Factor Analysis and Monte Carlo TRIDYN simulations. The comparison of experimental results with those obtained
from TRIDYN simulations suggests that the chemical reaction with the nitrogen partial pressure and processes driven by residual
defects are the rate-controlling mechanisms during the reactive IBM of V/Al interfaces. The kinetics of mixing is characterized
by two stages. During the first stage (≤4×1016 ions/cm2), the formation of vanadium nitride is observed. In the second stage, vanadium nitride is transformed into a V–Al–N ternary
nitride due to Al incorporation in the near surface region. Moreover, the V/Al ratio can be varied in a broad range, whereas
the nitrogen concentration slightly decreases with increasing the aluminium content of the film. 相似文献
6.
Roland Schmidt Erik McNellis Wolfgang Freyer Daniel Brete Tanja Gießel Cornelius Gahl Karsten Reuter Martin Weinelt 《Applied Physics A: Materials Science & Processing》2008,93(2):267-275
Self-assembled monolayers (SAMs) of 4-trifluoromethyl-azobenzene-4′-methyleneoxy-alkanethiols (CF3– C6H4–N=N–C6H4–O–(CH2)
n
–SH on (111)-oriented poly-crystalline gold films on mica were examined by X-ray photoelectron spectroscopy (XPS) and X-ray
absorption spectroscopy (XAS). The spectra are analyzed with the help of density-functional-theory calculations of the isolated
molecule. Only one doublet is detected in the sulphur 2p spectra of the investigated SAMs, consistent with a thiolate bond of the molecule to the gold surface. The C 1s XP spectra and the corresponding XAS π
* resonance exhibit a rich structure which is assigned to the carbon atoms in the different chemical surroundings. Comparing
XPS binding energies of the azobenzene moiety and calculated initial-state shifts reveals comparable screening of all C 1s core holes. While the carbon 1s XPS binding energy lies below the π
*-resonance excitation-energy, the reversed order is found comparing core ionization and neutral core excitation of the nitrogen 1s core-hole of the azo group. This surprising difference in core-hole binding energies is interpreted as site-dependent polarization
screening and charge transfer among the densely packed aromatic moieties. We propose that a quenching of the optical excitation
within the molecular layer is thus one major reason for the low trans to cis photo-isomerization rate of azobenzene in aromatic-aliphatic
SAMs. 相似文献
7.
Eu(III)-9-acridinecarboxylate (9-ACA) complex was synthesized and characterized by elemental analysis, conductivity measurement,
IR spectroscopy, thermal analysis, mass spectroscopy, 1H-NMR, fluorescence and ultraviolet spectra. The results indicated that the composition of this complex is [Eu(III)-(9-ACA)2(NCS)(C2H5OH)2] 2.5 H2O and the oxygen of the carbonyl group coordinated to Eu(III). The interaction between the complex with nucleotides guanosine
5′- monophosphate (5′-GMP), adenosine 5′-diphosphates (5′-ADP), inosine (5′-IMP) and CT-DNA was studied by fluorescence spectroscopy.
The fluorescence intensity of Eu(III)-9-acridinecarboxylate complex was enhanced with the addition of CT-DNA. The effect of
pH values on the fluorescence intensity of Eu(III) complex was investigated. Under experimental conditions, the linear range
was 9–50 ng mL−1 for calf thymus DNA (CT- DNA) and the corresponding detection limit was 5 ng mL−1. The results showed that Eu(III)-(9-ACA)2 complex binds to CT-DNA with stability constant of 2.41 × 104 M . 相似文献
8.
A. K. Dharmadhikari J. A. Dharmadhikari D. Mathur 《Applied physics. B, Lasers and optics》2009,94(2):259-263
Filamentation occurs within a 1.5 cm-long crystal of BaF2 during the propagation of intense, ultrashort (40 fs) pulses of 800 nm light; a systematic study as a function of incident
power enables us to extract quantitative information on laser intensity within the condensed medium, the electron density
and the six-photon absorption cross section. At low incident power, a single filament is formed within the crystal; two or
more filaments are observed along the direction transverse to laser propagation at higher incident powers. Further, due to
fluorescence from six-photon absorption (6PA), we are able to map the intensity variation in the focusing–refocusing cycles
along the direction of laser propagation. At still higher incident powers, we observe splitting of multiple filaments. By
measuring the radius (L
min ) of single filament inside BaF2, we obtain estimates of peak intensities (I
max ) and electron densities (ρ
max ) to be 3.26×1013 W cm−2 and 2.81×1019 cm−3, respectively. Use of these values enables us to deduce that the 6PA cross-section in BaF2 is 0.33×10−70 cm12 W−6 s−1. 相似文献
9.
Y. W. Li Z. G. Hu F. Y. Yue W. Z. Zhou P. X. Yang J. H. Chu 《Applied Physics A: Materials Science & Processing》2009,95(3):721-725
(La0.5Sr0.5)CoO3 (LSCO) thin films have been fabricated on silicon substrate by the pulsed laser deposition method. The effects of substrate
temperature and post-annealing condition on the structural and electrical properties are investigated. The samples grown above
650°C are fully crystalline with perovskite structure. The film deposited at 700°C has columnar growth with electrical resistivity
of about 1.99×10−3 Ω cm. The amorphous films grown at 500°C were post-annealed at different conditions. The sample post-annealed at 700°C and
10−4 Pa has similar microstructure with the sample in situ grown at 700°C and 25 Pa. However, the electrical resistivity of the
post-annealed sample is one magnitude higher than that of the in situ grown sample because of the effect of oxygen vacancy.
The temperature dependence of resistivity exhibits semiconductor-like character. It was found that post-annealing by rapid
thermal process will result in film cracks due to the thermal stress. The results are referential for the applications of
LSCO in microelectronic devices. 相似文献
10.
L. Pereira A. Morozov M. M. Fraga T. Heindl R. Krücken J. Wieser A. Ulrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(3):325-334
The temperature dependences of the quenching rate constants of the states
N2 (${\rm C} \ {^{3}{
\rm \Pi }_{u}}${\rm C} \ {^{3}{
\rm \Pi }_{u}} v′=0,1) by N2 (X) and of the state
N2 (${\rm C} \ {^{3}{
\rm \Pi }_{u}} \ v^{\prime}=0${\rm C} \ {^{3}{
\rm \Pi }_{u}} \ v^{\prime}=0) by O2 (X) are studied.
Time-resolved light emission from the gas was analyzed in the temperature
range from 300 K to 210 K keeping the gas at constant density. In case of
quenching by N2 (X), the quenching rate constant for the vibrational
level v′= 0 increases by (13 ±3)% with gas cooling whereas the
quenching rate constant for v′= 1 decreases by (5.0 ±2.5)% in this
temperature range. For quenching by O2 (X), the quenching rate constant
decreases by (3 ±2)% with gas cooling. The temperature variation of
the N2 (C 3Πu v′=0) emission intensity for pure nitrogen
and dry air are calculated using the obtained quenching rate constants and
is compared with the experimental data available in the literature. 相似文献
11.
M. Naglis 《The European Physical Journal C - Particles and Fields》2009,61(4):835-840
The PHENIX experiment at RHIC has measured a variety of light neutral mesons (π
0, K
S
0, η, ω, η
′, φ) via multi-particle decay channels over a wide range of transverse momentum. A review of the recent results on the production
rates of light mesons in p + p and their nuclear modification factors in d + Au, Cu + Cu and Au + Au collisions at different
energies is presented. 相似文献
12.
Tuning of the emission color of organic electroluminescent devices by exciplex formation at the organic solid interface 总被引:1,自引:0,他引:1
′ ,4′′-tris(3-methylphenylphenylamino)triphenylamine, 1,3,5-tris[(4-diphenylaminophenyl)phenylamino]benzene, N, N′-bis(3-methylphenyl)-N, N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine, and 4,4′,4′′-tri(N-carbazolyl)triphenylamine, emitted bright light resulting from the exciplex formed at the solid interface between TPOB
and the hole-transporting material. The exciplex formation was evidenced by the measurements of the photoluminescence spectra
and lifetimes of the mixture of an equimolar amount of TPOB and each of the hole-transporting materials. Tuning of the emission
color from greenish blue to orange was attained by varying the ionization potential of the hole-transporting material for
the fixed electron-transporting material of TPOB.
Received: 27 July 1998/Accepted: 28 July 1998 相似文献
13.
In this work, the performance of the solid extractants with polyacrylonitrile (PAN) binding matrix was studied for the separation
of lanthanides and actinides from nitric acid solutions. As extractants, incorporated into the PAN matrix, the N,N′-dimethyl-N,N′-dibutyltetradecylmalonamide
(DMDBTDMA), N,N′-dimethyl-N,N′-dioctyl-hexy-loxyethylmalonamide (DMDOHEMA), N,N,N′,N′-tetraoctyldiglycolamide (TODGA), 6,6′-bis-(5,6-dipentyl-[1,2,4]triazin-3-yl[2,2′]bipyridinyl
(C5BTBP) were used. Weight distribution coefficients Dg of europium and several actinides have been determined for all the composite materials. The kinetics of europium uptake,
practical dynamic extraction capacities, and extraction isotherms were also determined. The results obtained revealed that
the solid extractants studied are prospective for the partitioning of lanthanides and actinides from liquid radioactive wastes. 相似文献
14.
Pankaj Kumar S. C. Jain Vikram Kumar Suresh Chand R. P. Tandon 《The European physical journal. E, Soft matter》2009,28(4):361-368
Current-voltage (J -Vcharacteristics of poly(3-hexylthiophene) (P3HT) are studied at different temperatures upto high voltages ∼ 20 V in the hole-only
device configuration. The characteristics are studied in the temperature range 310-210K. In the intermediate voltage range
the J -V characteristics follow J
V
l+1 , where l > 1 . As the voltage increases to high values J still varies as a power law i.e. as Vm, but contrary to the literature result m becomes < 2 . This behavior is explained theoretically in terms of non-zero injection Schottky barriers. The complete analytical
expressions for the actual trap filled limit voltage (V′
TFL) and J -V curves beyond V′
TFL are presented. 相似文献
15.
Hongfei Jiang Guilan Wang Wenzhu Zhang Xiaoyu Liu Zhiqiang Ye Dayong Jin Jingli Yuan Zhiguang Liu 《Journal of fluorescence》2010,20(1):321-328
Because highly luminescent lanthanide compounds are limited to Eu3+ and Tb3+ compounds with red (Eu, ~615 nm) and green (Tb, ~545 nm) emission colors, the development and application of time-resolved
luminescence bioassay technique using lanthanide-based multicolor luminescent biolabels have rarely been investigated. In
this work, a series of lanthanide complexes covalently bound silica nanoparticles with an excitation maximum wavelength at
335 nm and red, orange, yellow and green emission colors has been prepared by co-binding different molar ratios of luminescent
Eu3+–Tb3+ complexes with a ligand N,N,N1,N1-(4′-phenyl-2,2′:6′,2′′-terpyridine-6,6′′-diyl)bis(methylenenitrilo) tetrakis (acetic acid) inside the silica nanoparticles.
The nanoparticles characterized by transmission electron microscopy and luminescence spectroscopy methods were used for streptavidin
labeling, and time-resolved fluoroimmunoassay (TR-FIA) of human prostate-specific antigen (PSA) as well as time-resolved luminescence
imaging detection of an environmental pathogen, Giardia lamblia. The results demonstrated the utility of the new multicolor luminescent lanthanide nanoparticles for time-resolved luminescence
bioassays. 相似文献
16.
Zhang Ye Hao Yuying Meng Weixin Xu Huixia Wang Hua Xu Bingshe 《Applied Physics A: Materials Science & Processing》2012,106(3):709-715
The electroplex between (2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazole) zinc [Zn(4-TfmBTZ)2] as an electron-acceptor and N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) as an electron-donor was
characterized by bilayer, blend, and multilayer quantum-well (MQW) device, respectively. The blend composition and quantum-well
number are effective parameters for tuning electroluminescence color. White light with high color purity and color rendering
index (CRI) was observed from these devices based on Zn(4-TfmBTZ)2/NPB. Moreover, the blend and MQW devices all exhibit high operation stability, hence excellent color stability. For the device
with 5 mol% NPB in blend layer, its Commission International Del’Eclairage (CIE) coordinate region is x=0.28–0.31, y=0.33–0.35 and CRI is 83.3–91.2 at 5–9 V. For MQW structure device with NPB of 60 nm thickness, its CIE coordinate region
is x=0.29–0.32, y=0.31–0.34 and CRI=87.9–92.5 at 10–15 V. Such high color stability and purity and CRI, being close to ideal white light, are
of current important for white OLED. 相似文献
17.
Mauro Castellani Ingo Salzmann Philippe Bugnon Shuwen Yu Martin Oehzelt Norbert Koch 《Applied Physics A: Materials Science & Processing》2009,97(1):1-9
We report on the structural and electronic interface formation between ITO (indium-tin-oxide) and prototypical organic small
molecular semiconductors, i.e., CuPc (copper phthalocyanine) and α-NPD (N,N′-di(naphtalen-1-yl)-N,N′-diphenyl-benzidine). In particular, the effects of in situ oxygen plasma pretreatment of
the ITO surface on interface properties are examined in detail: Organic layer-thickness dependent Kelvin probe measurements
revealed a good alignment of the ITO work function and the highest occupied electronic level of the organic material in all
samples. In contrast, the electrical properties of hole-only and bipolar organic diodes depend strongly on the treatment of
ITO prior to organic deposition. This dependence is more pronounced for diodes made of polycrystalline CuPc than for those
of amorphous α-NPD layers. X-ray diffraction and atomic force microscopic (AFM) investigations of CuPc nucleation and growth evidenced a
more pronounced texture of the polycrystalline film structure on the ITO substrate that was oxygen plasma treated prior to
organic layer deposition. These findings suggest that the anisotropic electrical properties of CuPc crystallites, and their
orientation with respect to the substrate, strongly affect the charge carrier injection and transport properties at the anode
interface. 相似文献
18.
W. Huang R. Richert 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,66(2):217-221
We investigate the nonlinear dielectric effects in a polar viscous liquid, propylene carbonate, by analyzing the voltage and
current traces obtained for a sinusoidal electric field at a frequency of 1 kHz and field amplitudes as high as 162 kV/cm.
The main source of non-linear behavior results from the energy absorbed from the field and is understood quantitatively. However,
there is a qualitative difference in the behavior of the field induced change, Δε′′(E), and the third harmonic amplitude of the current, I3ω. Although both Δε′′(E) and I3ω are considered reliable measures of non-linear behavior, we show here that the third harmonic signal reflects only those
non-linear responses that are instantaneous on the time scale of the test frequency. 相似文献
19.
Guido Mann Jens Vogel Rüdiger Preuß Pouya Vaziri Mohammadali Zoheidi Markus Eberstein Jörg Krüger 《Applied Physics A: Materials Science & Processing》2008,92(4):853-857
High-power optical multimode fibers are essential components for materials processing and surgery and can limit the performance
of expensive systems due to breakdown at the end faces. The aim of this paper is the determination of laser-induced damage
thresholds (LIDT) of fibers (FiberTech) and preforms (Heraeus Suprasil F300). Preforms served as models. They were heated
up to maximum temperatures of 1100, 1300 and 1500°C and cooled down to room temperature at rates of 10 K min−1 (oven) and ∼105 K min−1 (quenched in air) to freeze in various structural states simulating different conditions similar to a drawing process during
the production of fibers. Single- and multi-pulse LIDT measurements were done in accordance with the relevant ISO standards.
Nd:YAG laser pulses with durations of 15 ns (1064 nm wavelength) and 8.5 ns (532 nm) at a repetition rate of 10 Hz were used.
For the preforms, LIDT values (1-on-1) ranged from 220 to 350 J/cm2 (1064 nm) and from 80 to 110 J/cm2 (532 nm), respectively. A multi-pulse impact changed the thresholds to lower values. The LIDT (1064 nm wavelength) of the
preforms can be regarded as a lower limit for those of the fibers. 相似文献
20.
Chien-Chon Chen Jin-Shyong Lin Eric Wei-Guang Diau Tzeng-Feng Liu 《Applied Physics A: Materials Science & Processing》2008,92(3):615-620
Self-cleaning of a surface of nanotube arrays of anodic titanium oxide (ATO) is demonstrated. The ATO was prepared in fluoride
ion containing sulfate electrolytes with a structure of 0.4 μm length, 100 nm pores diameter, 120 nm interpore distance, 25 nm
pore wall thickness, a 8×109 pores cm−2 pore density, and 68.2% porosity. Prepared as thin films either directly from a Ti foil or on a glass substrate, these arrays
have the property that water drops spread quickly over the surface of the films without irradiation. In contrast, a flat anatase
TiO2 film requires irradiation with UV light for several minutes before the contact angle decreases to zero. The observed self-cleaning
behavior of the ATO thin films is due to the capillary effect of the nanochannel structure and the superhydrophilic property
of the anatase TiO2 surface inside the tube. 相似文献