共查询到20条相似文献,搜索用时 15 毫秒
1.
K. Yamamoto Y. Koga S. Fujiwara F. Kokai R.B. Heimann 《Applied Physics A: Materials Science & Processing》1998,66(1):115-117
3 bonds in the carbon films prepared by pulsed laser deposition of carbon obtained from graphite was investigated by electron
energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS). The fraction of sp3 bonds increased with a decreasing laser wavelength. Energetic C+ ion species were effectively produced by using a short-wavelength laser. The sp3 bond fraction increased with an increasing amount of energetic C+ ion species. The fractions of sp3 bonds in the carbon film were 80%, 42%, 26% and 15% at wavelengths of 193, 248, 532 and 1064 nm, respectively.
Received: 28 October 1997/Accepted:29 October 1997 相似文献
2.
F. Kokai K. Yamamoto Y. Koga S. Fujiwara R.B. Heimann 《Applied Physics A: Materials Science & Processing》1998,66(4):403-406
x ) films in a nitrogen atmosphere within the range 5×10-4–4×10-1 Torr. In the presence of a magnetic field, the emission intensities of N2 (second positive system) and CN species in the graphite ablation plumes were altered significantly, depending on the pressure
of the N2 environment. Corresponding to an intense CN emission, a magnetic field-induced enhancement of N incorporation – for example,
up to 37% at an N2 pressure of 300 mTorr – and the formation of sp3 tetrahedral CN bonding were both observed in the films. This suggests that the arrival of CN species at the substrate surface
with kinetic energies is important for film deposition.
Received: 27 August 1997/Accepted: 8 September 1997 相似文献
3.
The deposition rates of permalloy and Ag are monitored during pulsed laser deposition in different inert gas atmospheres.
Under ultrahigh vacuum conditions, resputtering from the film surface occurs due to the presence of energetic particles in
the plasma plume. With increasing gas pressure, a reduction of the particle energy is accompanied with a decrease of resputtering
and a rise in the deposition rate for materials with high sputtering yield. In contrast, at higher gas pressures, scattering
of ablated material out of the deposition path between target and substrate is observed, leading to a decrease in the deposition
rate. While in the case of Xe and Ar these processes strongly overlap, they are best separated in He. A He pressure of about
0.4 mbar should be used to reduce the kinetic energy of the deposited particles, to reach the maximum deposition rate and
to avoid implantation of the particles. This is helpful for the preparation of stoichiometric metallic alloy films and multilayers
with sharp interfaces.
Received: 27 March 2002 / Accepted: 3 April 2002 / Published online: 5 July 2002 相似文献
4.
An analytical method for simulating gas phase film growth has been developed and used to study the growth of diamond films
during prolonged deposition, i.e. the film thickness is much larger than the lateral grain size. From a model system composed
of 104 grains, reliable results can be evaluated for the growth of diamond films by (111) and (001) deposition under different initial
conditions and with varying growth parameters. It is demonstrated that the rate of structure evolution is sensitively influenced
by the aspect ratio of diamond crystal. A near-linear proportionality between the average grain size and the thickness of
films can be approximately yielded for a large film thickness which is about 10 times of the average distance of the nuclei.
The proportionality constant varies for a statistical nucleation from 0.0056 to 0.43 by changing the aspect ratio. Furthermore,
the orientational distribution is drastically narrowed down so that the probability of coalescence of grains with a slight
orientational difference is considerably increased.
Received: 28 September 2000 / Accepted: 19 February 2001 / Published online: 3 May 2001 相似文献
5.
H. Minami D. Manage Y.Y. Tsui R. Fedosejevs M. Malac R. Egerton 《Applied Physics A: Materials Science & Processing》2001,73(5):531-534
We have compared the quality of carbon films deposited with magnetically guided pulsed laser deposition (MGPLD) and conventional
pulsed laser deposition (PLD). In MGPLD, a curved magnetic field is used to guide the plasma but not the neutral species to
the substrate to deposit the films while, in conventional PLD, the film is deposited with a mixture of ions, neutral species
and clusters. A KrF laser pulse (248 nm) was focused to intensities of 10 GW/cm2 on a carbon source target and a magnetic field strength of 0.3 T was used to steer the plasma around a curved arc to the
deposition substrate. Electron energy loss spectroscopy was used in order to measure the fraction of sp3 bonding in the films produced. It is shown that the sp3 fraction, and hence the diamond-like character of the films, increased when deposited only with the pure ion component by
MGPLD compared with films produced by the conventional PLD technique. The dependence of film quality on the laser intensity
is also discussed.
Received: 7 December 2000 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
6.
X.Y. Chen K.H. Wong C.L. Mak J.M. Liu X.B. Yin M. Wang Z.G. Liu 《Applied Physics A: Materials Science & Processing》2002,74(5):703-706
Selective growth of single-oriented (110), (100) and (111) MgO films on Si (100) substrates without buffer layers was obtained
via a two-step method by pulsed laser deposition. It was found that the orientation of the films was determined at the initial
deposition stage by the substrate temperature only. The ambient pressure during deposition, the laser fluence and the etching
of the Si substrates have no apparent effect on the orientation of the films, but affect their crystalline quality. Under
the present deposition conditions, the surfaces of all three different single-oriented films were very smooth and devoid of
any particulates.
Received: 23 January 2001 / Accepted: 6 June 2001 / Published online: 2 October 2001 相似文献
7.
We report on the first layer growth of a Mn6+-doped material. Large-size BaSO4 substrates of 10×6×4 mm3 were grown from a LiCl solvent by the flux method. Flat surfaces of undoped BaSO4 were then achieved by use of liquid-phase epitaxy (LPE) from a CsCl–KCl–NaCl solvent. Finally, BaSO4:Mn6+ layers were grown by LPE with growth velocities of approximately 3 μm h-1, at temperatures of 550–508 °C. Absorption, luminescence, luminescence-excitation and luminescence-decay measurements confirmed
the incorporation of manganese solely in its hexavalent oxidation state. This material possesses potential as a near-infrared
tunable laser with a wavelength range larger than Ti:sapphire.
Received: 7 January 2002 / Revised version: 30 March 2002 / Published online: 8 August 2002 相似文献
8.
The orientation-selective growth of LaNiO3 films on Si(100) by pulsed laser deposition using a MgO buffer 总被引:4,自引:0,他引:4
X.Y. Chen K.H. Wong C.L. Mak J.M. Liu X.B. Yin M. Wang Z.G. Liu 《Applied Physics A: Materials Science & Processing》2002,75(4):545-549
Highly (100)-oriented, (110)-oriented and polycrystalline LaNiO3 (LNO) films were successfully prepared on Si(100) using an oriented MgO film as a buffer. It was somewhat surprising to find
that that the orientation relation between the LNO film and the corresponding MgO buffer was: LNO(100)\MgO(110), LNO(110)\MgO(111)
and LNO(polycrystalline)\MgO(100). The crystalline quality of the LNO films was shown to be sensitive to the preparation conditions
of the MgO buffer. The film surface was very smooth, without micrometer-sized droplets being observed. All LNO films were
of metallic conductivity, with a room-temperature resistivities of approximately 250, 280 and 420 μΩ cm for the (110)-oriented,
(100)-oriented and polycrystalline LNO, respectively.
Received: 2 April 2001 / Accepted: 23 October 2001 / Published online: 3 June 2002 相似文献
9.
A. Tselev A. Gorbunov W. Pompe 《Applied Physics A: Materials Science & Processing》1999,69(3):353-358
Spatial and energetic characteristics of the plasma plume by cross-beam pulsed-laser deposition (CBPLD) were investigated.
Effective droplets filtering together with high efficiency of material usage are observed by this approach. Time-of-flight
(TOF) technique with electrostatic ion collectors (Langmuir probes operating in the ion-collecting mode) were applied to obtain
kinetic energy distribution functions of ionized particles and to compare the ionization degrees of the plasma by the CBPLD
and by the conventional PLD. The average and maximum kinetic energies of the ions by the CBPLD are found to be 2–3 times lower
as compared to the conventional PLD. At the same time, the fraction of ionized species and highly exited neutrals (Rydberg
atoms) in the CBPLD plasma is 1.5–2 times larger in comparison to the conventional approach. Re-sputtering of the material
of the growing film by fast ions is a considerable effect in both the PLD methods by the chosen experimental conditions. The
angular width of the directional pattern of the plasma plume by CBPLD is comparable to that typical for the conventional PLD.
Received: 21 December 1998 / Accepted: 28 March 1999 / Published online: 7 July 1999 相似文献
10.
R.A. Gunasekaran J.D. Pedarnig M. Dinescu 《Applied Physics A: Materials Science & Processing》1999,69(6):621-624
A parametric study of the growth of La0.5Sr0.5CoO3 (LSCO) thin films on (100) MgO substrates by pulsed-laser deposition (PLD) is reported. Films are grown under a wide range
of substrate temperature (450–800 °C), oxygen pressure (0.1–0.9 mbar), and incident laser fluence (0.8–2.6 J/cm2). The optimum ranges of temperature, oxygen pressure, and laser fluence to produce c-axis oriented films with smooth surface morphology and high metallic conductivity are identified. Films deposited at low
temperature (500 °C) and post-annealed in situ at higher temperatures (600–800 °C) are also investigated with respect to their
structure, surface morphology, and electrical conductivity.
Received: 20 November 1998 / Accepted: 6 July 1999 / Published online: 21 October 1999 相似文献
11.
X. Zhu S. Lu H.L.W. Chan C.L. Choy K.H. Wong 《Applied Physics A: Materials Science & Processing》2003,76(2):225-229
Compositionally graded (Ba1-xSrx)TiO3 (BST) (x:0.0∼0.25) thin films were grown on Pt (111)/TiO2/SiO2/Si (100) substrates using layer-by-layer pulsed laser deposition in the temperature range 550–650 °C. Both downgraded (Ba/Sr
ratio varying from 100/0 at the bottom surface to 75/25 at the top surface) and upgraded (Ba/Sr ratio varying from 75/25 at
the bottom surface to 100/0 at the top surface) BST films were prepared. Their microstructures were systematically studied
by X-ray diffractometry and scanning electron microscopy. A grain morphology transition from large ‘rosettes’ (>0.30 μm) to
small compact grains (70–110 nm) was observed in the downgraded BST films as the deposition temperature was increased from
550 to 650 °C. No such grain morphology transition was detected in the upgraded BST films. Dielectric measurements with metal
electrodes revealed an enhanced dielectric behavior in the downgraded films. This enhancement is mainly attributed to the
large compressive stress field built up near the interface between the downgraded film and substrate. Furthermore, the BaTiO3 layer in the downgraded BST films not only serves as a bottom layer but also as an excellent seeding layer for enhancing
the crystallization of the subsequent film layers in the downgraded films.
Received: 10 December 2001 / Accepted: 12 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Corresponding author. Fax: 86-25/359-5535, E-mail: xhzhu@public1.ptt.js.cn 相似文献
12.
C. Popov P. Petkov Y. Nedeva P. Ilchev W. Kulisch 《Applied Physics A: Materials Science & Processing》2003,77(1):145-147
Thin chalcogenide films from the systems (GeSe4)1-xGax and (GeSe5)1-xGax with gallium contents up to 20 at. % have been prepared by vacuum evaporation and their stress has been investigated by a
cantilever technique. The addition of gallium to the Ge-Se matrix plays an important role in stress formation in the films:
films without gallium possess negligible stress, while all gallium-containing films are under compressive stress. The increase
of the gallium content leads to structural changes and an increase in the density, which results in higher stress values.
For all films, stress reduction with time is observed due to spontaneous relaxation.
Received: 2 October 2002 / Accepted: 22 November 2002 / Published online: 28 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-561/8044-136, E-mail: popov@schottky.physik.uni-kassel.de 相似文献
13.
Z.Y. Chen J.P. Zhao T. Yano T. Ooie 《Applied Physics A: Materials Science & Processing》2002,75(2):213-216
Raman characteristics of carbon nitride films synthesized by nitrogen-ion-beam-assisted pulsed laser deposition were investigated.
In addition to the D (disorder) band and G (graphitic) band commonly observed in carbon nitride films, two Raman bands located
at 1080–1100 and 1465–1480 cm-1 were found from our carbon nitride films. These two bands were well matched with the predicted Raman frequencies for βC3N4 and the observed Raman bands reported for carbon nitride films, indicating their relation to carbon-nitrogen stretching vibrations.
Furthermore, the relative intensity ratio of the two Raman bands to the D and G bands increased linearly with increasing nitrogen
content of the carbon nitride films.
Received: 30 October 2000 / Accepted: 5 February 2001 / Published online: 2 October 2001 相似文献
14.
J.M. Fernández-Pradas G. Sardin J.L. Morenza 《Applied Physics A: Materials Science & Processing》2003,76(2):251-256
Calcium phosphate coatings were deposited with a KrF excimer laser onto titanium alloy to study their homogeneity. Deposition
was performed at a high deposition rate under a water vapour atmosphere of 45 Pa and at a substrate temperature of 575 °C.
Samples were also submitted to annealing under the same conditions of deposition for different times just after deposition.
The effects of the annealing were also investigated. The morphology of the coatings was studied by scanning electron microscopy.
Their structure and phase distribution was analysed by X-ray diffractometry and infrared and micro-Raman spectroscopies. Besides
the non-uniform thickness, the results reveal an inhomogeneity in the spatial distribution of calcium phosphate phases in
the coatings. The phase distribution can be almost completely correlated with the deposition rate. High deposition rates (0.5 nm/pulse)
occurring in the centre of deposition results in the formation of amorphous calcium phosphate, while lower deposition rates
favour the presence of hydroxyapatite and alpha tricalcium phosphate. At intermediate deposition rates, beta tricalcium phosphate
is found, probably because the superimposed effect of energetic particles bombardment. The annealing process promotes the
crystallisation of the amorphous material. The importance of the deposition rate in the phases obtained is stated after comparing
these results with a previous work where homogeneous hydroxyapatite coatings were obtained under the same conditions of laser
fluence, temperature and pressure, but at lower deposition rates.
Received: 22 November 2001 / Accepted: 12 March 2002 / Published online: 5 July 2002
RID="*"
ID="*"Corresponding author. Fax: +34-93/402-1138, E-mail: jmfernandez@fao.ub.es 相似文献
15.
S. Rey F. Antoni B. Prevot E. Fogarassy J.C. Arnault J. Hommet F. Le Normand P. Boher 《Applied Physics A: Materials Science & Processing》2000,71(4):433-439
Diamond-like carbon (DLC) films have been grown on Si substrates at ambient temperature by the pulsed-laser ablation technique,
using pulses of different durations both in the nano- and picosecond ranges and at various energy fluences. The stability
of these films was investigated as a function of thermal anneals performed in UHV conditions up to 1273 K. Their physico-chemical
properties have been characterized by different techniques including X-ray photo-emission, Auger electron and electron-energy-loss
spectroscopies, Raman scattering, spectroscopic ellipsometry and atomic-force microscopy. The thermal stability of the films
has been demonstrated to be related to their initial structural (sp3/sp2 ratio) and chemical (contaminant) properties. DLC layers prepared under optimized conditions have been found to show a very
good thermal stability up to 900 K.
Received: 4 Jule 2000 / Accepted: 6 July 2000 / Published online: 6 September 2000 相似文献
16.
Holmelund E. Thestrup B. Schou J. Larsen N.B. Nielsen M.M. Johnson E. Tougaard S. 《Applied Physics A: Materials Science & Processing》2002,74(2):147-152
Indium tin oxide (ITO) films have been deposited by pulsed laser deposition (PLD) at 355 nm. Even though the absorption of
laser light at the wavelength 355 nm is much smaller than that of the standard excimer lasers for PLD at 248 nm and 193 nm,
high-quality films can be produced. At high fluence and at high substrate temperatures, the specific resistivity of the films,
2–3×10-4 Ω cm, is comparable to values obtained with excimer lasers, whereas the resistivities obtained at room temperature are somewhat
higher than those of films produced by excimer lasers. The transmission coefficient of visible light, about 0.9, is also comparable
to values for films deposited by excimer lasers. The crystalline structure of films produced at 355 nm is similar to that
of samples produced by these lasers.
Received: 16 January 2001 / Accepted: 24 July 2001 / Published online: 17 October 2001 相似文献
17.
R. Dinu M. Dinescu J.D. Pedarnig R.A. Gunasekaran D. Bäuerle S. Bauer-Gogonea S. Bauer 《Applied Physics A: Materials Science & Processing》1999,69(1):55-61
Ferroelectric SrBi2Ta2O9 (SBT) films were grown by pulsed-laser deposition (PLD) at different substrate temperatures and fluences. A correlation between
film structure and ferroelectric properties is established. The dielectric function ε′ of thin SBT films shows a Curie–Weiss behavior well below the peak temperature Tmax and relaxor-like behavior in the vicinity of Tmax. Domain walls have a strong influence on the dielectric and ferroelectric properties and on the polarization fatigue of SBT
films below 100 °C. The formation of ferroelectric phases is favored at lower substrate temperatures by incorporating Bi2O3 template layers into the structure.
Received: 18 March 1999 / Accepted: 19 March 1999 / Published online: 5 May 1999 相似文献
18.
N. Huber J. Heitz D. Bäuerle R. Schwödiauer S. Bauer H. Niino A. Yabe 《Applied Physics A: Materials Science & Processing》2001,72(5):581-585
KrF excimer-laser ablation of sintered-powder polytetrafluoroethylene (PTFE) targets is used for the deposition of high-quality
PTFE films on metallic microstructures and metal backplates for electroacoustic applications. The films are found to be highly
crystalline, consisting of large spherulites with diameters up to 1 mm. X-ray photoelectron spectroscopy of the films revealed
the chemical similarity of press-sinter target pulsed-laser-deposited films with bulk PTFE. Negatively charged PTFE films
on stainless steel backplates exhibit an exceptional charge stability with practically no decrease of the surface potential
up to 225 °C in open-circuit thermally stimulated discharge.
Received: 20 December 2000 / Accepted: 20 December 2000 / Published online: 23 March 2001 相似文献
19.
D.M. Bubb B.R. Ringeisen J.H. Callahan M. Galicia A. Vertes J.S. Horwitz R.A. McGill E.J. Houser P.K. Wu A. Piqué D.B. Chrisey 《Applied Physics A: Materials Science & Processing》2001,73(1):121-123
Thin films of polyethylene glycol (PEG) of average molecular weight, 1400 amu, were deposited by both matrix-assisted pulsed
laser evaporation (MAPLE) and pulsed laser deposition (PLD). The deposition was carried out in vacuum (∼10-6 Torr) with an ArF (λ=193 nm) laser at a fluence between 150 and 300 mJ/cm2. Films were deposited on NaCl plates, Si(111) wafers, and glass slides. The physiochemical properties of the films are compared
via Fourier transform infrared spectroscopy (FTIR), electrospray ionization (ESI) mass spectrometry, and matrix-assisted laser
desorption and ionization (MALDI) time-of-flight mass spectrometry. The results show that the MAPLE films nearly identically
resemble the starting material, whereas the PLD films do not. These results are discussed within the context of biomedical
applications such as drug delivery coatings and in vivo applications where there is a need for transfer of polymeric coatings
of PEG without significant chemical modification.
Received: 2 March 2001 / Accepted: 5 March 2001 / Published online: 23 May 2001 相似文献
20.
V. Brien A. Dauscher P. Weisbecker F. Machizaud 《Applied Physics A: Materials Science & Processing》2003,76(2):187-195
The preparation in thin film form of the known icosahedral phase in Ti-Ni-Zr bulk alloys has been investigated as a function
of substrate temperature. Films were deposited by pulsed laser deposition on sapphire substrates at temperatures ranging from
room temperature to 350 °C. Morphological and structural modifications have been followed by grazing-incidence and θ–2θ X-ray
diffraction, transmission electron diffraction and imaging. Chemical composition has been analyzed by electron probe microanalysis.
The in-depth variation of composition has been studied by secondary neutral mass spectroscopy. We show that pulsed laser deposition
at 275 °C makes the formation of a 1-μm-thick film of Ti-Ni-Zr quasicrystalline textured nanocrystallites possible.
Received: 7 June 2001 / Accepted: 18 February 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +33-3/8357-6300, E-mail: brien@mines.u-nancy.fr 相似文献