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1.
Y.H. Wang  S.J. Peng  R.W. Wang  Y.L. Mao 《Vacuum》2008,83(2):412-415
Metal nanocluster composite glass prepared by 200 keV Ag ions' implantation into silica with dose of 2 × 1017 ions/cm2 has been studied. The formation of sandwiched nanocluster-nanovoid-nanocluster structures has been evidenced by in situ transmission electron microscopy experiment (TEM). Fast nonlinear optical refraction and nonlinear optical absorption coefficients were measured at 532 nm and 1064 nm of wavelength by the Z-scan technique. The third-order nonlinear susceptibility χ(3) of this kind of sample was determined to be 4.0 × 10−8 esu at 532 nm and 9.0 × 10−8 esu at 1064 nm, respectively.  相似文献   

2.
Metal nanocluster composite glass was formed by Cu ion implantation into silica using metal vapor vacuum arc (MEVVA) ion source. The microstructural properties of the nanoclusters were analyzed by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters were measured at 1064 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility were deduced. The mechanisms responsible for the nonlinear response were discussed. Third-order nonlinear susceptibility χ(3) of this kind of sample was determined to be (4.2 ± 1.0) × 108 esu.  相似文献   

3.
G. Sahu  B. Joseph  G.S. Roy 《Vacuum》2009,83(5):836-3477
Effect of implantation fluence on the total number of metal atoms incorporated in a host matrix at few tens of keV beam energy has been studied experimentally using Rutherford backscattering spectrometry (RBS) as well as using simple calculations, taking Au and Ag ions for host matrices Si and silica glass. In all the cases, calculations showed that the total number of retained metal atoms are identical to the implantation fluence upto 3 × 1016 ions cm−2 above which the metal content retained in the matrix shows a saturation. The variation in the number of metal atoms as a function of the implantation fluence extracted from the RBS measurements has been found to be in good agreement with the results of the calculation expect for the high fluence implantation case of Ag in Si. This observed difference is attributed to the irradiation induced in-diffusion of Ag atoms in Si matrix due to the low diffusion activation energy of Ag in Si. Effect of saturation on the number of metal atoms incorporated in the matrix is reflected in the Raman scattering data of the implanted Si samples as well as the optical absorption data of the implanted silica glass samples.  相似文献   

4.
Haisong Wang  N. Kishimoto 《Vacuum》2008,82(11):1168-1171
The optical propagation property of a planar waveguide with a periodic nanoparticle grating layer is characterized by using sliding prism method. Here, Cu nanoparticle grating was fabricated on a-SiO2 substrate by periodic heavy-ion irradiation technique. The pitch of these gratings was 2 μm and 3 μm, respectively. The flux and fluence were at the range of 6-10 μA/cm2 and 6 × 1016-1 × 1017 ions/cm2, respectively. The grating effect, mainly including the mode selection effect, is observed. The effect depends on the pitch of the grating and the morphology of nanoparticles. The propagation loss of the waveguide induced by nanoparticle layer is evaluated.  相似文献   

5.
Optical absorption and nonlinear absorption were studied for Ag nanoparticle composite. Negative Ag ion with 60 keV were applied for implanting into amorphous-SiO2 at a flux 3 μA/cm2 to total fluences ranging from 3 × 1016 to 1 × 1017 ions/cm2. Absorption spectra of Ag-implanted amorphous-SiO2 showed a surface plasmon peak resulting from formation of nanoparticles. The strength of the resonance reflected from the local electric field inside the nanoparticle induced by an external electric field. Nonlinear optical constants were evaluated by the z-scan method with a tunable femtosecond laser system. The strength of the nonlinearity also reflected from the local electric field. Nonlinear absorption coefficients exhibit a maximal value of −3.6 × 103 m/GW for Ag:SiO2 at 420 nm (2.95 eV), around the surface plasmon resonance.  相似文献   

6.
Planar optical waveguides in Nd:BSO crystals were fabricated by the implantation of 500 keV He ions and 6.0 MeV C ions at two different substrate temperatures. The guiding modes were measured by the prism-coupling method with a He-Ne beam at 633 nm. The intensity calculation method (ICM) and reflectivity calculation method (RCM) were used for reconstructing refractive index profiles. The near-field intensity distribution of the waveguide, formed by He and C ions implanted after annealing at 300 °C, was measured by the end-face coupling setup. It was in reasonable agreement with the intensity of the waveguide mode simulated by the finite-difference beam propagation method (FD-BPM). The absorption spectra of the sample with He ions implanted at fluences of 3 × 1016 ions/cm2 were measured using a spectrophotometer.  相似文献   

7.
Planar optical waveguides formed by Si ion implantation into PECVD SiO2 have been characterized by the dark mode spectroscopy method at a wavelength of 0.6328 μm. The measured effective index values of the guided modes have been used to investigate the optical properties of the core layers of the waveguides after different pre-implantation treatments. It was found that annealing the specimens before implantation, affected both the refractive index and thickness of the core layers. In the annealed specimens a thicker core layer and a larger relative refractive index difference between the core and the buffer layer resulted.  相似文献   

8.
The single beam Z-scan technique has been used to measure the third-order nonlinear refractive index, γ, the two-photon absorption coefficient, ß, and the variation of refractive index per unit photoexcited carrier density σr, and the free carrier absorption cross section σab for quantum-confined Fe2O3 nanoparticles coated by a layer of organic molecular in toluene and bare particles in hydrosol. For coated Fe2O3 nanoparticles, the ratio γ/ß is enhanced by a factor of five compared to the bare sample. Their figures of merit related to linear and two-photon absorption for ultrafast all-optical devices application were determined.  相似文献   

9.
Y.H. Wang  S.J. Peng  R.W. Wang  Y.G. Cheng 《Vacuum》2008,83(2):408-411
Metal nanoparticles synthesized by sequentially ion-implanted Ag and Cu into silica glasses have been studied. The implantation doses (×1016 ions/cm2) were 5Ag, 5Cu and 5Ag/5Cu, respectively. The optical and microstructural properties of the nanoparticles were characterized by optical absorption spectra and transmission electron microscopy (TEM), respectively. Fast nonlinear optical refraction and nonlinear optical absorption coefficients were measured at 1064 nm of wavelength using Z-scan technique. Results in this paper indicate that the nonlinear refractive index for the Ag/Cu implanted system has a higher value compared to single Ag or Cu implantation nanoparticles.  相似文献   

10.
Abstract

The polytetrafluoroethylene (PTFE), which was implanted with Ni ion to different energy and doses, fabricated metallic structures by selective electroless copper plating. The characteristic and microstructure of the copper film were studied using SEM and X-ray diffraction. Friction performance of the interface between copper film and basal body of PTFE was tested with a CETR UMT-2 (CETR Co., Campbell, CA, USA) multifunction micromechanics instrument. The test loads were 10, 20 and 40 N, while the line velocity was 8 mm s?1, and the frequency of data acquisition was 1 Hz. The Ni ion implantation replaces the complicated electroless plating surface pretreatment, and it is an assisted technique of electroless plating of copper on the surface of PTFE and plate Cu directly on its surface. Continuous, prepressing and uniformity plating was obtained with proper technique parameters and the dosage of Ni+. The frictional performance comprehensive property of copper film was remarkably influenced by different plating methods, annealing treatment and testing loads under unlubricated condition. The friction coefficients and wear rates changed with the varied load. Annealing treatment improves the tightness and uniformity of the copper film, while it decreases its cavity. Friction performance of copper film was thus increased. The mechanisms of friction and wear of copper film under different test conditions are also discussed.  相似文献   

11.
Sequential multi-energy implantations of zinc and sulphur ions have been performed in a 250-nm thick SiO2 layer thermally grown on 1 1 1 silicon. Energies and doses have been chosen to produce 10 at.% constant concentration profiles overlapping over about 100 nm. Manganese is subsequently introduced at various levels by the same way. Thermal treatments (from 700 to 1100 °C) lead to the formation of nanometric precipitates of the luminescent compound ZnS:Mn. A bimodal size distribution is observed, with a quasi-single layer of large particles (40 nm) in the end-of-range region and much smaller precipitates between this layer and the surface. The orange emission is maximal when the Mn concentration is close to 3%. Several hours at 900 °C is the best thermal budget for maximal luminescence intensity at room temperature. A shift of the excitation spectrum related to size variations, shows that the particles of smaller size are mainly responsible for the observed luminescence. In agreement with other authors, the luminescence lifetime is found in the ms range and increases with the nanocrystal diameter, tending to the lifetime of bulk ZnS. The luminescence of ZnS:Mn nanoparticles embedded in SiO2 by ion implantation is also shown to be very stable during long UV light irradiation.  相似文献   

12.
Polycarbonate samples were implanted with 100 keV N+ ions at fluences 1015, 1016 and 5 × 1016 ions cm−2. Drastic alterations in UV-Visible transmittance spectra were observed which are interrelated with change in surface color and optical absorption of the implanted samples. UV-Visible transmission studies show that at ion fluence of 1016 ions cm−2, transmission approaches to zero at about λ = 427 nm and below up to 200 nm. Optical band gap (EOPT) reduces with increase in fluence and at maximum ion fluence of 5 × 1016 N+ cm−2, EOPT was determined to be 1.56 eV whereas for pristine its value was 3.00 eV. Raman analysis indicates the formation of amorphous carbon on the surface of polycarbonate at an ion fluence of 1016 N+ cm−2. Rise in fluence to 5 × 1016 N+ cm−2 results in enhancement in disorder on the surface of the host polymer. Modifications in the structural arrangements were found to be in strong association with changes in optical properties with increase in ion fluence and the same is discussed.  相似文献   

13.
C.J. Pan  G.C. Chi  B.J. Pong  C.Y. Chang 《Vacuum》2009,83(7):1073-1075
Nitrogen ions were implanted into melt-grown ZnO (0001) substrates and subsequently annealed at 800 °C under an oxygen ambient. The photoluminescence spectrum of N+-implanted ZnO excited by a He-Cd laser exhibited donor-acceptor pair (DAP) transition emission at 385 nm with a full width at half maximum of 30 nm at 10 K. The DAP emission is associated with the acceptor energy of nitrogen in ZnO, calculated to be 170 meV. Defect-related red emission at about 610 nm observed in N+-implanted ZnO was due to the residual damage from the implantation step because it was also observed in Ar+-implanted ZnO but not in un-implanted ZnO annealed at 800 °C under the same oxygen ambient.  相似文献   

14.
Synthesis of metal nanoparticles by ion implantation has a number of advantages. Nevertheless, certain remaining difficulties must be overcome in order to optimize the characteristics of ion-implanted nanocomposites. The principle among these are the lack of control over the size distribution and position of the precipitates within the implanted layer. Two-dimensionally ordered arrangements of Ag nanoparticles are formed in Ag-implanted silica glass by post-implanted Cu ions. The spherical Ag nanoparticles are formed to align at the same deep depth in the silica. Cross-sectional transmission electron microscopy revealed that the Ag nanoparticles are a size of 35-48 nm in diameter. The evolution of nanoparticles is characterized by transmission electron microscopy.  相似文献   

15.
In this study, the irradiation coloring effects by 60 keV protons on space applied lens coated with a MgF2/ZrO2/Al2O3 optical multilayer antireflection film were investigated by ground experiment and computer simulation methods. The energy loss within each layer of the antireflection film caused by proton irradiation was calculated using SRIM program based on the Monte Carlo simulation approach. It was shown that the lower energy proton irradiation led to a smaller range, but induced larger energy loss, resulting in worse damage in the antireflection film. Degradation in spectrum transmission of the lens irradiated by 60 keV protons using a synthesized space irradiation simulation facility was examined. Evolutions of the color centers in the irradiated films were also evaluated by absorption spectrometry techniques. It was found that the F2 color centers in the MgF2 film, and the VōH and F2+ color centers in the Al2O3 film are responsible for the absorption bands at 370 nm, 400 nm and 440-450 nm, respectively. The absorption band at 490 nm was caused by F+ color centers in the ZrO2 film, and the absorption band at 580-660 nm was induced by some impurity color centers.  相似文献   

16.
Accelerator based MeV ion implantation of Ca2+ and P2+ into the titanium substrate to form hydroxyapatite (HA) has been carried out. Calcium hydroxide was formed after heating the calcium implanted titanium in air at 80 °C for 3 h. Upon subsequent annealing for 5 min at 600 °C HA was formed on the surface. Penetration depth of the HA layer in this method is much higher as compared to keV ion implantation. By elemental analysis, Ca/P ratio of the HA was found to be 1.76 which is higher than the ideal 1.67. This higher Ca/P ratio is attributed to the higher penetration depth of the MeV technique used.  相似文献   

17.
Uniaxially strained SiGe layers were fabricated with a newly developed selective-ion-implantation technique. The SiGe layer was grown on the Si substrate, into which laterally selective ion-implantation with stripe pattern was carried out prior to the SiGe growth. A strain-relaxation of the SiGe layer was largely enhanced due to ion-implantation-induced defects selectively in the ion-implanted area while it was hardly enhanced in the neighboring unimplanted area. However, micro-Raman mapping and X-ray diffraction reciprocal space mapping measurements obviously revealed that the relaxed SiGe in the implanted area remarkably influenced a strain state of the neighboring strained SiGe in the unimplanted area, that is, the strain along the stripe line direction was highly relieved due to the stress caused by the neighboring relaxed SiGe while the strain in the direction perpendicular to the line was well maintained. As a result, highly asymmetric strain state, that is, uniaxial strain was realized, where 4 times different relaxation ratios in the two directions were observed. These results indicate that the selective-ion-implantation technique developed in this study has a high potential to realize uniaxially strained Si/Ge channel devices with high mobility.  相似文献   

18.
The degradation rate is important to biodegradable magnesium materials. In this study, Zn is implanted using a cathodic arc source into pure magnesium at an accelerating voltage of 35 kV. The nominal ion implant fluence is 2.5 × 1017 ions cm−2. After Zn implantation, the degradation rate in simulated body fluids is increased significantly. It is postulated that because Zn exists in the metallic state in the implanted layer, the galvanic effect between the Zn rich surface region and magnesium matrix induces the observed accelerated degradation.  相似文献   

19.
There is a growing interest in the carbon ceramics and their use in present technology. Among other problems, the joining of such ceramics with other materials presents an important challenge. Since joining with metals is associated with wetting, we studied the effect of ion implantation on wetting of various forms of carbon and of silicon carbide by copper. An essential result is that Ti ion implantation followed by ArcPVD Ti deposition results in excellent wettability in all studied cases.  相似文献   

20.
We report the change in optical absorption properties of InGaN epilayers around the critical layer thickness determined from X-ray diffraction. Detrimental sub-band gap absorption is observed in InGaN thin films grown beyond the critical layer thicknesses, and is caused by localized electric fields around extended crystalline defects and aided by V-defects through light channeling. The photoluminescence response from InGaN thin films, grown beyond the critical layer thickness, is reduced owing to absorption of the incident laser light by non-radiative recombination extended crystalline defects. The formation of V-defects is observed to occur beyond the critical layer thickness and continues to grow in areal coverage aiding in sub-band gap absorption. This optical behavior sets constraints to be incorporated in the design of InGaN solar cell and requirement for improvement in epitaxial growth techniques to reduce V-defects.  相似文献   

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