共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
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.
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
5.
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
6.
J.A. Chaos J. Gonzalo C.N. Afonso J. Perrière M.T. García-González 《Applied Physics A: Materials Science & Processing》2001,72(6):705-710
Laser ablation of single-crystal LiNbO3 in a gas environment is used to grow films on (100) Si substrates heated to 650 °C. The film composition and crystallinity
are studied as a function of the nature (reactive, O2, or inert, Ar) and pressure of the gas environment applied during deposition and cooling-down processes, the laser energy
density and the target–substrate distance. Experimental results show that a gas pressure close to 1 mbar is required to produce
stoichiometric films in either O2 or Ar. The modification of the laser energy density and the target–substrate distance allows us to improve the crystallinity
of the films that become textured along the (006) direction. The influence of the experimental parameters on the film properties
is discussed in the frame of the formation of a blast wave, that leads to the focusing of the expanding Li species and thus,
to the increase of the Li content in the films.
Received: 8 February 2001 / Accepted: 9 February 2001 / Published online: 3 May 2001 相似文献
7.
G. Radhakrishnan R.E. Robertson R.C. Cole P.M. Adams 《Applied Physics A: Materials Science & Processing》2003,77(2):175-184
Titanium carbide (TiC) is one of the preferred coatings for improving the performance of macroscopic moving mechanical components
due to its established wear-resistance. Pulsed laser deposition (PLD) is an excellent method for depositing TiC, because unlike
any other deposition process for TiC, PLD offers the capability of producing high-quality films even at room temperature.
Using a modified PLD technique, especially designed for the deposition of particulate-free films, TiC coatings have been deposited
at room temperature on silicon (Si) and on several types of thin films typically employed for fabricating microelectromechanical
systems (MEMS). Our results demonstrate that TiC coatings also offer a high wear-resistance to Si surfaces, which in turn
has led to our application of TiC to “moving” Si MEMS devices. The performance of moving Si MEMS devices is limited by their
poor operational lifetimes, which have been attributed to the excessive wear at sliding Si interfaces. The work presented
here describes a hybrid process, whereby PLD is used in conjunction with a user-friendly Si surface micromachining scheme
for inserting wear-resistant TiC coatings between critical sliding Si interfaces in MEMS devices. This paper describes the
properties of PLD-TiC for MEMS and the hybrid PLD-surface micromachining process for the integration of TiC coatings into
Si MEMS.
Received: 23 January 2003 / Accepted: 8 February 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +1-310/563-7614, E-mail: gouri.radhakrishnan@aero.org 相似文献
8.
Z.-M. Ren P.-N. Wang Y.-C. Du Z.-F. Ying F.-M. Li 《Applied Physics A: Materials Science & Processing》1997,65(4-5):407-409
2 radicals when the 355 and 1064 nm outputs of a Nd:YAG laser were applied. While for the 532 nm ablation, a relatively higher
concentration of excited atomic carbon was obtained. Different Raman and FTIR spectral features were observed from the deposited
films with different ablation wavelengths. The 532 nm laser ablation is proposed for the synthesis of high quality carbon
nitride films.
Received: 16 October 1996 / Accepted: 11 April 1997 相似文献
9.
Evolution of the deposition rate during pulsed laser deposition of hydroxyapatite coatings and its relation with target morphology 总被引:1,自引:0,他引:1
J.M. Fernández-Pradas L. Clèries P. Serra G. Sardin J.L. Morenza 《Applied Physics A: Materials Science & Processing》2001,72(5):613-618
The evolution of the deposition rate during pulsed laser deposition of hydroxyapatite coatings with a KrF excimer laser was
studied. This evolution was related to the changes produced on the target morphology during laser irradiation. Laser fluences
in the 1.0–5.2 J/cm2 range, typical for the deposition of hydroxyapatite coatings, were investigated. Deposition rates were measured through a
quartz-crystal microbalance, and the target surface was observed by scanning electron microscopy. At the lowest fluences,
the deposition rate decreases as the number of pulses increases. At the same time, a cone structure is developed on the target
surface. At the highest fluences, the deposition rate increases with the number of pulses. In this case, the target surface
becomes rough but cones are not formed. In all cases, an enlargement of the effective irradiated area results. This enlargement
produces the effect of fluence dilution and also an increase of the emitting area. These opposite effects could account for
the different evolutions found for the deposition rate. At low fluences the effect of fluence dilution would predominate over
the increase of the emitting area, and at high fluences the second effect would predominate over the first.
Received: 28 September 2000 / Accepted: 4 October 2000 / Published online: 10 January 2001 相似文献
10.
R. Diamant L. Ponce M. Fernández E. Jiménez 《Applied physics. B, Lasers and optics》1998,66(5):639-643
2 range). From this data, various emitting species were identified at different regions of the expanding plasma. Plasma temperatures
were inferred from the continuous broad background. The velocity of one of the emitting species was calculated from time resolved
data. The grown films were characterised by AES and XRD. The role of cadmium is shown to be most important considering the
relationship between the plasma emission and the resulting film properties.
Received: 16 May 1997/Revised version: 29 September 1997 相似文献
11.
R. Serna C.N. Afonso C. Ricolleau Y. Wang Y. Zheng M. Gandais I. Vickridge 《Applied Physics A: Materials Science & Processing》2000,71(5):583-586
The processes leading to the formation of Cu:Al2O3 composite films on Si (001) with a well defined nanostructure by alternate pulsed laser deposition (a-PLD) in vacuum are
investigated. Alternately amorphous Al2O3 layers and Cu nanocrystals nucleated on the Al2O3 surface are formed, according to the PLD sequence. The Al2O3 deposited on the Cu nanocrystals fills in the space between them until they are completely buried, and subsequently, a continuous
dense layer with a very flat surface (within 1 nm) is developed. The nucleation process of the nanocrystals and their resulting
oblate ellipsoidal shape are discussed in terms of the role of the energetic species involved in the PLD process and the metal–oxide
interface energy.
Received: 4 July 2000 / Accepted: 5 July 2000 / Published online: 13 September 2000 相似文献
12.
The experimental parameters that control the surface morphology and size of iron cobalt nanoparticles synthesized at room temperature by pulsed laser ablation deposition (PLAD) technique have been systematically investigated. The nanoparticle synthesis has been achieved at higher operating gas pressures of argon. It was found that nanoparticles upon deposition formed small clusters, the size of which increases with decreasing pressure, increasing laser-energy density, and decreasing target-to-substrate distance. This trend could be attributed to change in the kinetic energy of deposited nanoparticles with varying argon pressure, laser-energy, and target-to-substrate distance. The nanoparticles size and size distribution showed strong dependence on argon pressure and weak dependence on laser-energy density and target-to-substrate distance. 相似文献
13.
R. Serna T. Missana C.N. Afonso J.M. Ballesteros A.K. Petford-Long R.C. Doole 《Applied Physics A: Materials Science & Processing》1998,66(1):43-47
Received: 1 September 1997/Accepted 8 September 1997 相似文献
14.
Y. Du M.-S. Zhang J. Wu L. Kang S. Yang P. Wu Z. Yin 《Applied Physics A: Materials Science & Processing》2003,76(7):1105-1108
SrTiO3 thin films were prepared on a fused-quartz substrate by pulsed laser deposition (PLD). Dense and homogeneous films with a
thickness of 260 nm were prepared. Optical constants (refractive index n and extinction coefficient k) were determined from
the transmittance spectra using the envelope method. The optical band gap energy of the films was found to be 3.58 eV, higher
than the 3.22 eV for bulk SrTiO3, attributable to the film stress exerted by the substrate. The dispersion relation of the refractive index vs. wavelength
follows the single electronic oscillator model. The refractive index and the packing density for the PLD-prepared SrTiO3 thin films are higher than those for the SrTiO3 films prepared by physical vapor deposition, sol–gel and RF sputtering.
Received: 18 March 2002 / Accepted: 7 October 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: mszhang@nju.edu.cn 相似文献
15.
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
16.
F. Di Fonzo D. Tonini A. Li Bassi C. S. Casari M. G. Beghi C. E. Bottani D. Gastaldi P. Vena R. Contro 《Applied Physics A: Materials Science & Processing》2008,93(3):765-769
Alumina is technologically exploited in several forms, ranging from compact hard films as protective coatings to open microstructures
of high specific area as supports for catalysts. Currently, various production processes are used to deposit the different
forms. PLD has the potential of obtaining not only the different forms, but also a continuous modulation of properties, by
tuning of the process parameters. This work investigates the relationship between the process parameters and the resulting
film morphology, structure and properties for PLD performed with an alumina target in a background oxygen atmosphere. Three
distinct growth regimes are found, leading, respectively, to compact homogeneous films, columnar structures and open microstructures.
These structures are quantitatively characterized, and the ranges of the process parameters corresponding to the three regimes
are identified. An empirical scaling law is proposed, which can be exploited as a guide for the design of growth processes
aimed at obtaining specific film properties. 相似文献
17.
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
18.
Z. F. Li Z. Y. Yang R. F. Xiao 《Applied Physics A: Materials Science & Processing》1996,63(3):243-246
Visible photoluminescence (PL) has been observed from the hydrogenated amorphous carbon (a-C:H) films prepared by ArF pulsed laser ablation of polymethyl methacrylate (PMMA) in the presence of hydrogen gas (H2). With increasing hydrogen concentration the PL intensity increases and the intensity maximum blue-shifted. The PL intensity also increases after hours of light illumination, exhibiting a light soaking enhancement. Increasing the deposition temperature decreases the PL and increases the ratio of sp3/sp2 bonds.Z.F. Li is on leave from Department of Physics, Nanjing University, Nanjing 210093, P.R. China. 相似文献
19.
D.M. Bubb B. Toftmann R.F. Haglund Jr. J.S. Horwitz M.R. Papantonakis R.A. McGill P.W. Wu D.B. Chrisey 《Applied Physics A: Materials Science & Processing》2002,74(1):123-125
Thin films of the biodegradable polymer poly(DL-lactide-co-glycolide) (PLGA) were deposited using resonant infrared pulsed
laser deposition (RIR-PLD). The output of a free-electron laser was focused onto a solid target of the polymer, and the films
were deposited using 2.90 (resonant with O-H stretch) and 3.40 (C-H) μm light at macropulse fluences of 7.8 and 6.7 J/cm2, respectively. Under these conditions, a 0.5-μm thick film can be grown in less than 5 min. Film structure was determined
from infrared absorbance measurements and gel permeation chromatography (GPC). While the infrared absorbance spectrum of the
films is nearly identical with that of the native polymer, the average molecular weight of the films is a little less than
half that of the starting material. Potential strategies for defeating this mass change are discussed.
Received: 22 August 2001 / Accepted: 23 August 2001 / Published online: 17 October 2001 相似文献
20.
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