共查询到20条相似文献,搜索用时 15 毫秒
1.
Mingsong Wang Xiaonong Cheng Juan Yang 《Applied Physics A: Materials Science & Processing》2009,96(3):783-787
ZnO thin films were prepared by RF magnetron sputtering. The photoluminescence dependence on the growth ambient and annealing
temperatures and the atmosphere has been studied. Visible photoluminescence with blue, green, orange, and red emission bands
has been demonstrated by controlling the preparation conditions. Complete suppression of the visible emission bands was also
realized by annealing the O2-ambient-grown samples in N2 atmosphere at higher temperatures, which indicated the preparation of ZnO thin films with high optical quality. 相似文献
2.
A. P. Caricato M. Lomascolo A. Luches F. Mandoj M. G. Manera M. Mastroianni M. Martino R. Paolesse R. Rella F. Romano T. Tunno D. Valerini 《Applied Physics A: Materials Science & Processing》2008,93(3):651-654
Methoxy Ge Triphenylcorrole [Ge(TPC)OCH3] has been recently synthesized and deposited as thin film by the Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique.
In the last few years, corroles have been the object of an increasing number of studies and MAPLE technique seems to be a
very promising deposition method for organic and polymeric films, producing good results for applications in chemical gas
sensing layers production. In this work Ge(TPC)OCH3 thin films were deposited by both spin coating and MAPLE techniques for comparison. The morphology of the films was investigated
by Atomic Force Microscopy (AFM), while their optical properties were analyzed by photoluminescence (PL) and UV-vis absorption
measurements and were compared with the ones of the starting solution. The film absorption spectrum presented the same peaks
with the same relative intensities of that recorded in solution. The luminescence spectra were acquired periodically to evaluate
the aging effects and no detectable variations were recorded over a period of 1 month. 相似文献
3.
Multilayer optical memory using femtosecond-laser induced fluorescence in rare-earth ion doped glass
Ki-Soo Lim Jongho Shin Kyungsik Jang Sunkyun Lee Douglas S. Hamilton 《Applied Physics A: Materials Science & Processing》2008,93(1):215-218
We report three-dimensional fluorescent memory by recording optical bits with irradiation of femtosecond laser pulses at 800 nm
and by reading photoluminescence change in Eu3+ doped glass. We produced multi-layered micro-bit patterns and read the blue emission from the 405 and 325 nm excitations
due to permanent reduction of Eu3+ to Eu2+ in sodium borate glass by scanning the irradiated region in multilayers. 相似文献
4.
S. Heiroth Th. Lippert A. Wokaun M. Döbeli 《Applied Physics A: Materials Science & Processing》2008,93(3):639-643
Yttria-stabilized zirconia (YSZ) is the most common solid electrolyte material used e.g. in ceramic fuel cells. Thin films
of YSZ were deposited on c-cut sapphire single crystals by pulsed laser deposition using a KrF excimer laser focused on a polycrystalline 8 mol% Y2O3-stabilized ZrO2 target. Depending on the substrate temperature and the oxygen background pressure during deposition, different microstructures
are obtained. XRD and high-resolution SEM revealed the formation of dense amorphous films at room temperature. At 600°C preferentially
(111) oriented polycrystalline films consisting of densely agglomerated nm-sized grains of the cubic phase resulted. Grain
size and surface roughness could be controlled by varying the oxygen background pressure. RBS and PIXE evidenced congruent
transfer only for a low number of pulses, indicating a dynamical change of the target stoichiometry during laser irradiation.
The in-plane ionic conductivity of the as-deposited crystalline films was comparable to bulk YSZ. The conductivity of initially
amorphous YSZ passes a maximum during the crystallization process. However, the relative changes remain small, i.e. no significant
enhancement of ionic conductivity related to the formation of a nanocrystalline microstructure is found. 相似文献
5.
C. Guo L. Luan X. Ding F. Zhang F. G. Shi F. Gao L. Liang 《Applied physics. B, Lasers and optics》2009,95(4):779-785
Eu2+ and Mn2+ co-activated Sr5(PO4)3Cl phosphors with blue and orange color double emission bands, under a broad-band excitation wavelength range of 340–400 nm,
were synthesized by the solid-state reaction. It was found that the processing parameters, including the fluxes, annealing
time and activators concentrations, affect the emission intensity and other luminescent properties. Energy transfer between
Eu2+ and Mn2+ was discovered and the transfer efficiency was also estimated based on relative intensities of Eu2+ and Mn2+ emission. Thus the relative strength of blue and orange emission intensities could be tuned by varying the relative concentration
of Eu2+ and Mn2+. Since the photoluminescence excitation spectra of the newly developed Sr5(PO4)3Cl:Eu2+, Mn2+ phosphors exhibit a strong absorption in the range of 340–400 nm, they are promising for producing UV-LED-based white LEDs. 相似文献
6.
Martin Pavlišta Martin Hrdlička Petr Němec Jan Přikryl Miloslav Frumar 《Applied Physics A: Materials Science & Processing》2008,93(3):617-620
Amorphous chalcogenide thin films were prepared from As2Se3, As3Se2 and InSe bulk glasses by pulsed laser deposition using a KrF excimer laser. Thickness profiles of the films were determined
using variable angle spectroscopic ellipsometry. The influence of the laser beam scanning process during the deposition on
the thickness distribution of the prepared thin films was evaluated and the corresponding equations suggested. The results
were compared with experimental data. 相似文献
7.
Satoshi Kurumi Yohei Shimizu Shotaro Kobayashi Kouichi Takase Kaoru Suzuki 《Applied Physics A: Materials Science & Processing》2008,93(3):741-743
We have attempted to control the photoluminescence spectrum of transparent p-type semiconductor (LaO)CuS to check possibilities of phosphor application using non-stoichiometric thin films prepared by
pulse laser deposition method. Two kinds of samples are examined, one is the samples that contain the excess S and the other
is the excess Cu. All samples are a single phase without impurities, regardless of heavily doping. Lattice constants for all
samples don’t depend on the concentration of excess atoms. Perhaps, this is due to the nature of the layered materials. Introduction
of excess atoms leads to change the photoluminescence spectra. The excess S and Cu have much effect on the red and the blue
luminescence bands, respectively. We have succeeded in the tuning luminescence band of photoluminescence spectra. 相似文献
8.
Etienne Shaffer Amr S. Helmy Dominique Drouin Jan J. Dubowski 《Applied Physics A: Materials Science & Processing》2008,93(4):869-874
We have investigated ArF (λ=193 nm) excimer laser-induced crystallization of amorphous CdSe semiconductor thin films. The crystallization has been monitored
by a related photoluminescence emission in the free-exciton and defect-band transition regions. For different irradiation
conditions, we have observed formation of nanorods, up to 2 μm long, as well as the formation of arrays of CdSe nanobeads
with a narrow size distribution and characteristic dimensions corresponding to λ/2 and λ/8. The successful crystallization has also been confirmed by confocal Raman spectroscopy. 相似文献
9.
Small-angle X-ray scattering (SAXS) off parallel,cylindrical, well-defined nanopores: from random pore distribution to highly ordered samples 总被引:1,自引:0,他引:1
Martin?Engel Bernd?Stühn J?rg?J.?Schneider Thomas?Cornelius Maike?Naumann 《Applied Physics A: Materials Science & Processing》2009,97(1):99-108
10.
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
11.
Wen-Yang Chang Te-Hua Fang Yu-Cheng Lin 《Applied Physics A: Materials Science & Processing》2008,92(3):693-701
Physical characteristics of polyimide films, including optical, micro/nano mechanical, and thermophysical characteristics
were investigated using a photometric, a nanoindentation, and a thermomechanical analyzer for applications in flexible sensors.
Experimental results show that UV light cannot transmit into the polyimide films. The transmittances, with a maximum of about
86%, at VIS and near IR lights decrease with increasing PI film thicknesses. The mechanical characteristics were determined
using tensile, bending moment, and nanoindentation testing. The stress–strain curve approximated bilinear characteristics,
the load–unload bending moment exhibited hysteresis, and nanoindentation generated elastic energy dissipation in the loading–unloading
region. Nanoindentation showed an almost uniform hardness and a reduced Young’s modulus of about 0.181±0.03 and 3.21±0.06 GPa,
respectively, when the penetrating depth was more than about 2 μm. Thermophysical characteristics were greatly influenced
on 8.3 and 25 μm specimens due to the higher relaxation of thin PI films. The thermal expansion remained steady when the thickness
was over 50 μm. The results show that PI films have potential in flexible sensing and higher temperature fabrication. 相似文献
12.
Daniel Kolacyak Heiko Peisert Thomas Chassé 《Applied Physics A: Materials Science & Processing》2009,95(1):173-178
Core hole screening effects at organic/metal interfaces were studied by core level X-ray photoemission spectroscopy (XPS),
X-ray excited Auger electron spectroscopy (XAES), and valence band ultraviolet photoemission spectroscopy (UPS). The comparison
of energetic shifts in XPS and XAES enables the estimation of electronic relaxation energy (screening ability). Magnesium
phthalocyanine (MgPc) and zinc phthalocyanine (ZnPc) evaporated on single crystalline Au(100) were used as model molecules.
Two different features in the Mg KLL spectra can be clearly separated for (sub-)monolayer coverages, while only minor changes
of the shape of Mg 1s are observed. Applying a dielectric continuum model, the major screening mechanism cannot be described
sufficiently by polarization screening due to mirror charges, significant contributions by charge transfer screening have
to be considered. In contrast, small screening effects in the bulk material can be explained by surface polarization. 相似文献
13.
Enrique Camps L. Escobar-Alarcón V. H. Castrejón-Sánchez P. Tolentino-Eslava 《Applied Physics A: Materials Science & Processing》2008,93(3):759-763
Amorphous carbon thin films were deposited by laser ablation of a graphite target, using the fundamental line of a 5 ns Nd:YAG
laser. Deposition was carried out as a function of the plasma parameters (mean kinetic ion energy and plasma density), determined
by means of a planar probe. In the selected working regimes the optical emission from the plasma is mainly due to atomic species,
namely C+ (426.5 nm); however, there is also emission from other atomic species and molecular carbon. The hardness and resistivity
could be varied in the range between 10 and 25 GPa, and 108 and 1011 Ω cm, respectively. The maximum values were obtained at a 200 eV ion energy and 6×1013 cm−3 plasma density, where the maximum quantity of C–C sp3 bonds was formed, as confirmed by Raman spectroscopy. 相似文献
14.
We report on the fabrication and characterization of planar and channel waveguides in KTiOPO4 crystals by 6.0 MeV C3+ ion implantation with the dose of 1×1014 ions/cm2. The dark mode spectroscopy of the planar waveguide was measured using a prism coupling arrangement. An increase of the both
n
x
and n
y
refractive indices induced by the annealing after implantation is believed to be responsible for waveguide formation. The
bright near-field intensity distribution of the transverse-electric and transverse-magnetic modes in the annealed channel
waveguide was collected and studied by end-coupling method. 相似文献
15.
The mechanism of nanobump formation in femtosecond pulse laser nanostructuring of thin metal films 总被引:1,自引:0,他引:1
Dmitriy S. Ivanov Baerbel Rethfeld Gerard M. O’Connor Thomas J. Glynn Alexey N. Volkov Leonid V. Zhigilei 《Applied Physics A: Materials Science & Processing》2008,92(4):791-796
The physical mechanisms responsible for the formation of nanobump structures on a surface of a thin metal film irradiated
by a tightly focused femtosecond laser pulse are investigated in a large-scale molecular dynamics simulation. The simulation
is performed with a combined atomistic-continuum model adapted for an adequate representation of laser-induced processes at
the length-scale of the entire laser spot. The relaxation of the compressive stresses generated by the fast laser heating
is identified as the main driving force responsible for the separation of the metal film from the substrate and formation
of the nanobump. The kinetics of the transient melting and resolidification, occurring under conditions of the fast cooling
due to the two-dimensional electron heat conduction, defines the shape of the nanobump. The predictions of the simulation
are related to the surface structures observed in femtosecond laser nanostructuring. 相似文献
16.
Shili Hou Huibing Mao Jiqing Wang Ziqiang Zhu Weiping Jing 《Applied Physics A: Materials Science & Processing》2009,94(4):795-797
Cadmium sulfide (CdS) quantum dots (QDs) prepared by a convenient chemical method have been characterized using absorption,
fluorescence, and photoluminescence excitation techniques. The photoluminescence excitation studies show that there is an
electron transfer from the surface adsorbate (thiourea) to CdS QDs in aqueous solution. The excitation band with peak maximum
at 5.8 eV is assigned to the electronic transitions in the chemisorbed thiourea, whereas the excitation band between 3.45
and 3.7 eV corresponds to the band-to-band transition within the nanocrystalline CdS host. The absorption spectroscopy of
the CdS QD solutions shows a strong absorption peak which is generated from thiourea. The band-edge fluorescence of the CdS
QDs has also been investigated. It is shown that the fluorescence property of the CdS QDs can be enhanced by adding cadmium
chloride (CdCl2) solution. 相似文献
17.
Tomoaki Sawabe Koshi Okamura Tomoki Sueyoshi Takashi Miyamoto Kazuhiro Kudo Nobuo Ueno Masakazu Nakamura 《Applied Physics A: Materials Science & Processing》2009,95(1):225-232
Vertical electrical conduction in Au/(polycrystal-line pentacene)/Al diode structures and the influence of the kinetic energy
of incident Au atoms on the conduction property have been comprehensively studied using current–voltage–temperature (I–V–T) measurements, ultraviolet photoelectron spectroscopy (UPS), atomic-force-microscope (AFM) current imaging, etc. In the I–V characteristics, a symmetrical ohmic current component appeared when a low voltage was applied, and a super-linear one appeared
when a high positive voltage was applied to Au. The component in the high-forward-voltage region was concluded to be a thermionic
emission of holes from Au with a 0.23-eV injection barrier, which is the normal hole conduction through the highest occupied
molecular orbital of pentacene. On the other hand, the ohmic component was concluded to be a metal-like electron transport
through high-density gap states at grain boundaries which were induced by the Au penetration into pentacene. UPS and I–V–T measurements clearly indicated the generation of the gap states and the enhancement of their density by the reduction of
Au kinetic energy. For vertical-type devices with polycrystalline organic films, the ohmic conduction through the grain boundary
will increase the leakage current. On the contrary, it possibly enhances the carrier injection in lateral-type transistors
in the case of top-contact configuration. 相似文献
18.
T. Shih M. T. Winkler T. Voss E. Mazur 《Applied Physics A: Materials Science & Processing》2009,96(2):363-367
Using a broad band dual-angle pump-probe reflectometry technique, we obtained the ultrafast dielectric function dynamics of
bulk ZnO under femtosecond laser excitation. We determined that multiphoton absorption of the 800-nm femtosecond laser excitation
creates a large population of excited carriers with excess energy. Screening of the Coulomb interaction by the excited free
carriers causes damping of the exciton resonance and renormalization of the band gap causing broadband (2.3–3.5 eV) changes
in the dielectric function of ZnO. From the dielectric function, many transient material properties, such as the index of
refraction of ZnO under excitation, can be determined to optimize ZnO-based devices. 相似文献
19.
The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd3+ ions in CaNb2O6 crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10−20 cm2 with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd3+ ions in CaNb2O6 crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω
t
are Ω
2=5.321×10−20 cm2,Ω
4=1.734×10−20 cm2,Ω
6=2.889×10−20 cm2. The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β
1=36.03%,β
2=52.29%,β
3=11.15%,β
4=0.533%. The emission cross section at 1062 nm is 9.87×10−20 cm2. 相似文献
20.
I. Marozau A. Shkabko G. Dinescu M. Döbeli T. Lippert D. Logvinovich M. Mallepell A. Weidenkaff A. Wokaun 《Applied Physics A: Materials Science & Processing》2008,93(3):721-727
Perovskite-type nitrogen substituted SrTiO3 thin films were deposited with a one-step process by RF-plasma assisted pulsed laser deposition from a SrTiO3 target using a N2 plasma, while deposition with a NH3 plasma yields films with almost no incorporated nitrogen. The deposited films exhibit a cubic perovskite-type crystal structure and reveal oriented growth on MgO(100) substrates. The unit cell parameters of the studied N-doped SrTiO3 films range within 3.905<a<3.918 Å, which is slightly larger than for SrTiO3 (a=3.905 Å). The nitrogen content in the deposited films varies from 0.2 to 0.7 atom%. The amount of incorporated nitrogen in the films decreases with increasing RF-power, while the N2 flow rate does not have any pronounced influence on the N content. Nitrogen incorporation results in an increased optical absorption at 400–600 nm, which is associated with N(2p) energy states that have a higher energy level than the valence band in strontium titanate. The optical band gap energies in the studied N-doped SrTiO3 films are at 3.2–3.3 eV, which is very similar to that of pure strontium titanate (~3.2 eV). Films deposited with NH3 for the RF-plasma exhibit a lower degree of crystallinity and reveal almost no nitrogen incorporation into the crystal lattice. 相似文献