共查询到20条相似文献,搜索用时 11 毫秒
1.
D. Praschak T. Bahners E. Schollmeyer 《Applied Physics A: Materials Science & Processing》2000,71(5):577-581
Surface modifications on polyethyleneterephthalate (PET) films following excimer UV lamp irradiation induced grafting were
studied. Characteristics of the modifications depending on the conditions during the irradiation were analysed using contact-angle
measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), differential scanning calorimetry (DSC)
and Fourier-transform infrared spectroscopy (FTIR). Depending on the conditions during the irradiation different surface modifications
were obtained, which can generally be classified regarding the hydrophilic or hydrophobic characteristics of the resulting
surface. It is shown that not every substance that meets the general demands will be grafted on synthetic polymers using excimer
UV radiation. Examples of agents that can simply be grafted onto polymer surfaces and those that undergo further crosslinking,
building up thin films are listed. Agents used for grafting on polymers are 1,5-hexadiene, perfluoro-4-methyl-pent-2-ene,
polyethyleneglycol 200, monosilane and polyethylene. The transferability of the effects achieved to substrates such as polyparaphenylene
terephthalamide or polymetaphenylene isophthalamide is shown.
Received: 23 June 2000 / Accepted: 28 June 2000 / Published online: 5 October 2000 相似文献
2.
L. Nánai I. Hevesi N. F. Bunkin B. A. Zon S. V. Lavrishev B. S. Luk'yanchuk G. A. Shafeev 《Applied Physics A: Materials Science & Processing》1990,50(1):27-34
We present experimental data for vanadium and copper oxidation by cw CO2 laser light in an external electric field. Direct influence of the external field on the crystallisation process has been demonstrated in both vanadium and copper cases; the oxidation rate and surface morphology depend sensitively on the sign and strength of the external field. 相似文献
3.
S. L. Gao R. Häßler E. Mäder T. Bahners K. Opwis E. Schollmeyer 《Applied physics. B, Lasers and optics》2005,81(5):681-690
UV irradiation has interesting potential for the photochemical modification of polymers. In order to study cross-linking effects
and/or thin-layer deposition following a treatment in the presence of bi-functional media or in inert atmosphere, irradiation
of PET in various atmospheres was performed using a KrCl excimer lamp. Surface properties were investigated by atomic force
microscopy, nanoindentation, micro-thermal analysis, and X-ray photo-electron spectroscopy. The studies reveal that surface
chemical composition, morphology, adhesion, thermomechanics, and stiffness/modulus are strongly affected by UV irradiation
in the presence of bi-functional media. Films treated in octadiene and argon show an increase of surface modulus, much less
expansion, and lower soft/melt temperatures, which is an indication of the surface cross-linking effect and a decrease of
crystallinity within the near-surface layer. In the case of a diallylphthalate-treated film, depending on the local structure,
either a strong decrease of melting temperature or no melting point is found, which is attributed to the irregular cross linking
and thickness of the modified layer associated with a decrease of surface modulus. A significant increase of the alkali resistance
is found after irradiation, as a result of both wetting and cross-linking effects on the polymer surface. 相似文献
4.
K. Chen J. Ihlemann P. Simon I. Baumann W. Sohler 《Applied Physics A: Materials Science & Processing》1997,65(4-5):517-518
3 by short ultraviolet laser pulses (0.5 ps, 248 nm) is presented. Gratings with a period of 360 nm and a modulation depth
of 80 nm are fabricated on the sample surface by single-laser-shot exposure. The structures are projection imaged by a Schwarzschild
objective in air. The modulation depth can be varied by applying multiple-pulse exposure.
Received: 18 July 1997/Accepted: 5 August 1997 相似文献
5.
O. L. Bourne D'Arcy Hart D. M. Rayner P. A. Hackett 《Applied Physics A: Materials Science & Processing》1994,59(3):295-297
A multilayered structure of GaAs and AlGaAs was depth profiled using the technique of digital etching. A single excimer laser (KrF) was used to control the etch rate and to identify each layer by monitoring the Ga ions generated during the desorption process. The Ga ions were the only ions observed and were only generated when the photon flux was in the GaAs layer. The etch rate, 0.9 monolayers (2.5 Å) per pulse, was constant with depth. The overall layer recognition resolution was 45 monolayers. 相似文献
6.
O. Yavas A. Schilling J. Bischof J. Boneberg P. Leiderer 《Applied Physics A: Materials Science & Processing》1997,64(4):331-339
with a pressure pulse width of . Additionally, the phase of an acoustic pulse is observed to change upon reflection at the liquid–solid interface if bubbles
are present, providing a direct proof for laser-induced bubbles.
Received: 5 December 1996/Accepted: 6 January
1997 相似文献
7.
T. Ohtsubo T. Azuma M. Takaura T. Higashiguchi S. Kubodera W. Sasaki 《Applied Physics A: Materials Science & Processing》2003,76(2):139-141
We have demonstrated the non-thermal removal of oxygen atoms from an oxidized silicon surface (SiO2) on a silicon wafer by the use of a low-power (0.3 mW cm-2) incoherent vacuum ultraviolet (VUV) light source at 126 nm. X-ray photoelectron spectroscopy (XPS) has shown that a maximum
Si concentration of 80% appears at the surface after a 20-h irradiation with 9.8 eV photons, as a result of oxygen removal
from the SiO2 matrix. The surface morphology, however, indicates no damage or melting on the surface even after the irradiation.
Received: 15 April 2002 / Accepted: 17 April 2002 / Published online: 10 September 2002
RID="*"
ID="*"Permanent address: Nano-Tech Photon Inc., Shimotomita 4132-1, Shintomi, Miyazaki, 889-1404, Japan
RID="**"
ID="**"Corresponding author. Fax: +81-985/583-899, E-mail: kubodera@opt.miyazaki-u.jp 相似文献
8.
M. R. Berman 《Applied Physics A: Materials Science & Processing》1991,53(5):442-448
Xenon chloride (308 nm) excimer laser-assisted etching of GaAs (100) in Cl2 was demonstrated and characterized with respect to laser and gas parameters. The etch rate increased linearly with laser fluence from thresholds in the range of 50 to 75 mJ/cm2 to the highest fluence studied, 650 mJ/cm2. For a laser fluence of 370 mJ/cm2, the etch rate varied with Cl2 pressure reaching a maximum at a Cl2 pressure of about 2 Torr. The etch rate decreased monotonically with Ar buffer gas pressure because of redeposition of GaCl3 products into the etched channel. The redeposited GaCl3 affected the etch rate and the etch morphology. The etch rate and morphology also varied with laser repetition rate. The mobility of chlorine on the surface also plays an important role in the etching mechanism. 相似文献
9.
The photodesorption and photodecomposition pathways of dimethylgold hexafluoroacetylacetonate, DMG (hfac), adsorbed on a cooled quartz substrate is reported for 222-nm KrCl excimer laser radiation. The time-of-flight (TOF) of neutral photoproducts, desorbed from the surface of the gold film formed during the experiment, were analyzed under collisionless conditions by a differentially-pumped mass spectrometer. Extensive dissociation of adsorbed DMG (hfac) into DMG and the hfac ligand was observed. The ligand was found to recombine with a CH3 radical on the surface. Translational energy distributions for the detected species were obtained by deconvoluting the TOF curves into a self-consistent set of Maxwell-Boltzmann distributions for the desorbed parent molecule, laser-induced decomposition products, and surface recombination reaction products. The implications of these results for the mechanistic details of the low-pressure, laser-assisted organometallic deposition of DMG(hfac) are discussed.ONT/NRL Research Associate (Nov. 1987-Oct. 1988)NRC/NRL Cooperative Research Associate 相似文献
10.
D. Dogas T. Efthimiopoulos C. Andreouli M. Campbell 《Applied Physics A: Materials Science & Processing》2001,73(3):287-294
Monitoring the amplitude and the delay of arrival of the pressure waves generated during the interaction of laser pulses with
YBCO in air, we can determine the vaporization and the ablation thresholds, the etching rate, the change of the acoustic wave
velocity and the effect of plasma shielding on the etching rate. The steep increase of the amplitude and the order-of-magnitude
increase of the etching rate above the ablation threshold, suggest that the laser–target coupling mechanism changes from (thermal)
vaporization below threshold to a rapid solid-to-gas phase transition. The dumping of the acoustic waves following the ablation
with successive laser pulses correlates with the evolution of the YBCO high-Tc superconductor surface morphology, which is known to relate to the deposition rate and the surface morphology of pulsed-laser-deposited
high-Tc thin films.
Received: 7 January 2000 / Accepted: 9 October 2000 / Published online: 25 July 2001 相似文献
11.
12.
T. Chassé A. Chassé H. Peisert P. Streubel 《Applied Physics A: Materials Science & Processing》1997,65(6):543-549
Received: 21 March 1997/Accepted: 12 August 1997 相似文献
13.
F. Havermeyer C. Pruner R.A. Rupp D.W. Schubert E. Krätzig 《Applied physics. B, Lasers and optics》2001,72(2):201-205
The absorption spectra of poly(methyl methacrylate) (PMMA) doped with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone
(DMPA) change under illumination with UV light. Time-resolved measurements of the kinetics of the absorption changes at 352 nm
prove the existence of a second light-induced reaction besides the expected light-induced decay of the photoinitiator. We
propose a model for this second process which is in good agreement with the observed experimental facts.
Received: 17 July 2000 / Published online: 5 October 2000 相似文献
14.
Ablation of organic polymers is described on the basis of photothermal bond breaking within the bulk material. Here, we assume
a first-order chemical reaction, which can be described by an Arrhenius law. Ablation starts when the density of broken bonds
at the surface reaches a certain critical value.
In order to understand the ablation behavior near the threshold fluence, φth, non-stationary regimes must be considered. The present treatment reveals several qualitative differences with respect to models that treat
ablation as a surface process: (i) Ablation starts sharply with a front velocity that has its maximum value just after the onset. (ii) The transition
to the quasi-stationary ablation regime is faster. (iii) Near threshold, the ablated depth h has a square-root dependence
on laser fluence, i.e., h∝(φ-φth)1/2. The ablation velocity is very high even near φth. (iv) With φ≈φth ablation starts well after the laser pulse. (v) The depletion of species is responsible for the Arrhenius tail observed with
fluences φ≤φth. (vi) Residual modification of material has maximum near the threshold. (vii) Stationary regimes of ablation demonstrate change of effective activation energy with laser intensity.
The model calculations are applied to Polyimide (KaptonTM H). Here, differences in single-pulse ablated depth determined from mass loss and profilometry should be about 10 nm.
Received: 16 February 1999 / Accepted: 18 February 1999 / Published online: 28 April 1999 相似文献
15.
Microstructures of micrometer sizes are produced on the surface of polyethylene terephthalate using nanosecond Nd:YAG-laser
irradiation at 266 nm wavelength. The stable and well-defined structures were investigated using scanning electron microscopy.
A theoretical model is suggested for the nonlinear behavior of etch depth versus incident laser fluence. In this model, two-photon
stepwise absorption of chromophores is the dominant mechanism.
Received: 3 August 2000 / Accepted: 9 January 2001 / Published online: 25 July 2001 相似文献
16.
S. Kuribayashi T. Tomimasu S. Kawanishi S. Arai 《Applied physics. B, Lasers and optics》1997,65(3):393-398
2 . The laser generates an intense infrared macropulse with a duration of 17 μs; the macropulse consists of a train of 380 micropulses,
each of which has a duration of a few picoseconds. The fluence of a macropulse was estimated to be about 16 Jcm-2 at a beam waist. Peak wavelengths were set in the range of 9–10 μm. The macropulse induced the IRMPD of 1 and 5 Torr CHBrF2; most of molecules in the focal region seemed to decompose at a wavelength of 9.3 μm. The mechanism is the initial decomposition
of CHBrF2 to CF2 and HBr, followed by the dimerization of CF2 to form C2F4. The decomposition was found to be isotopically selective at 9.7 μm; the final product C2F4 had a 13C atomic fraction of 6%. Th
e addition of CO2 to CHBrF2 significantly decreased the yield of C2F4. vibrationally excited CHBrF2 molecules produced by laser pulses were efficiently deactivated by CO2 molecules.
Received: 7 October 1996 相似文献
17.
U. Elrod M. Ch. Lux-Steiner M. Obergfell E. Bucher L. Schlapbach 《Applied physics. B, Lasers and optics》1987,43(3):197-201
X-ray photoemission spectroscopy (XPS) has been used to study the surface reaction of Zn3P2 single crystals.The spectra of crystals exposed to H2, O2, CO2, O2+H2O or CO2+H2O during a four week period were compared to the spectra of as-grown or in UHV scraped samples. For samples contaminated with the wet gases O2+H2O and CO2+H2O additional phosphorus core levels together with a shift of the zinc core levels were observed. For crystals exposed to atmosphere during several months no phosphorus could be detected on the gasgrown surface, whereas the stochiometry of Zn3P2 was maintained within the bulk. Crystals with scraped surfaces showed no moisture sensitivity. No surface contamination was also detected for Zn3P2 crystals deposited with up to 1000 L H2O or exposed to atmosphere during 30 min. 相似文献
18.
The deposition of lead film on quartz substrates by photolysing tetraethyl lead vapor with a laser is reported. The dependence of the deposition rate on the pressure of tetraethyl lead, on the light intensity and on the pressure of the buffer gas is measured. Deposition phenomena at low light intensity are discussed. 相似文献
19.
C. Lavoie M. Meunier R. Izquierdo S. Boivin P. Desjardins 《Applied Physics A: Materials Science & Processing》1991,53(4):339-342
Large area excimer laser induced deposition of titanium on fused silica from TiCl4 is studied with an emphasis on process modeling. We show that several TiCl4 monolayers can be adsorbed if the surface is adequately prepared and that the Ti thin film growth occurs through the photodecomposition of this adsorbed TiCl4 layer. We propose two growth regimes. During an initiation phase, up to 3 nm in thickness, the adsorbed layer is photochemically decomposed giving a growth rate of 0.015 nm/pulse. In a second phase, the deposition rate increases to between 2 and 7 nm/pulse due to the laser heating of the preceding photochemically deposited titanium film. Between consecutive pulses, TiCl4 molecules primarily from the adsorbed layer diffuse to the reaction zone leading to a new adsorbed layer ready to be transformed to solid titanium. 相似文献
20.
Clean ablation of poly(tetrafluoroethylene) (PTFE) at etch rates in excess of 7µm/pulse has been achieved with an excimer laser using 308nm radiation and a 25 ns pulse width. This was accomplished by doping the ultraviolet-transparent PTFE polymer with polyimide. Ablation rates were investigated as a function of fluence in the range from 1 to 12J/cm2 and dopant levels up to 15% (wt/wt). Results show that at a given fluence there exists an optimum absorption coefficient max, for which maximum ablation rates are achieved. The value of max was found to decrease with increasing fluence. The relationship between max and fluence was determined from existing ablation rate models and found to compare favorably with empirical results. 相似文献