共查询到20条相似文献,搜索用时 531 毫秒
1.
M. Jubera J. Villarroel A. García-Caba?es M. Carrascosa J. Olivares F. Agullo-López A. Méndez J. B. Ramiro 《Applied physics. B, Lasers and optics》2012,107(1):157-162
The propagation losses (PL) of lithium niobate optical planar waveguides fabricated by swift heavy-ion irradiation (SHI),
an alternative to conventional ion implantation, have been investigated and optimized. For waveguide fabrication, congruently
melting LiNbO3 substrates were irradiated with F ions at 20 MeV or 30 MeV and fluences in the range 1013–1014 cm−2. The influence of the temperature and time of post-irradiation annealing treatments has been systematically studied. Optimum
propagation losses lower than 0.5 dB/cm have been obtained for both TE and TM modes, after a two-stage annealing treatment
at 350 and 375∘C. Possible loss mechanisms are discussed. 相似文献
2.
B. N. Dash Priyadarshini Dash Haripriya Rath P. Mallick R. Biswal P. K. Kulriya N. C. Mishra 《Indian Journal of Physics》2010,84(10):1315-1320
We report the preparation of multiferroic BiFeO3 thin films on ITO coated glass substrates through sol-gel spin coating method followed by thermal annealing and their modification
by swift heavy ion (SHI) irradiation. X-ray diffraction and Raman spectroscopy studies revealed amorphous nature of the as
deposited films. Rhombohedral crystalline phase of BiFeO3 evolved on annealing the films at 550°C. Both XRD and Raman studies indicated that SHI irradiation by 200 MeV Au ions result
in fragmentation of particles and progressive amorphization with increasing irradiation fluence. The average crystallite size
estimated from the XRD line width decreased from 38 nm in pristine sample annealed at 550°C to 29 nm on irradiating these
films by 200 MeV Au ions at 1 × 1011 ions cm−2. Complete amorphization of the rhombohedral BiFeO3 phase occurs at a fluence of 1 × 1012 ions.cm−2. Irradiation by another ion (200 MeV Ag) had the similar effect. For both the ions, the electronic energy loss exceeds the
threshold electronic energy loss for creation of amorphized latent tracks in BiFeO3. 相似文献
3.
E. Landi A. Armigliato S. Solmi R. Kögler E. Wieser 《Applied Physics A: Materials Science & Processing》1988,47(4):359-366
The electrical activation of boron implanted in crystalline and preamorphized silicon has been investigated during rapid thermal
annealing performed with halogen lamps. Samples implanted with B+ fluences ranging between 5×1014 and 1×1016cm−2 and treated at temperatures between 900°C and 1100°C have been examined. When boron is implanted in crystalline Si, activation
proceeds slowly atT<1000°C and cannot be completed in times typical of rapid thermal annealing (a few tens of seconds). The analysis of carrier
profiles indicates that the time constant for activation is strongly affected by local damage and dopant concentration. If
the total boron concentration exceeds equilibrium solubility, precipitation occurs concomitant to activation, even if the
substitutional boron fraction is still lower than equilibrium solubility. ForT≧1000°C complete activation is obtained in times of about 10 s. In the case of preamorphized Si the activation occurs very
quickly, during the recrystallization of the amorphous layer, for all the examined temperatures. 相似文献
4.
Thomaz R. S. de Souza C. T. Papaléo R. M. 《Applied Physics A: Materials Science & Processing》2011,104(4):1223-1227
We report on the effect of light-ion irradiation on the size distribution of etched tracks produced by medium energy heavy-ions
in polycarbonate. Makrofol KG polycarbonate foils were treated with 2 MeV H+ ions at different fluences φ either before or after a short irradiation with 18 MeV Au7+. The heavy ion irradiation was used to produce the latent tracks in the foils and the proton beam acted as a perturbation
to the matrix. The proton irradiation causes initially a decrease in the mean etched pore size, as compared to samples only
bombarded by Au ions, reaching a minimum at H+ fluences around 2–5×1013 cm−2, while at higher φ the pore size starts to grow again. This effect is attributed to the action of two competitive processes that dominate in
different fluence regimes. The decrease in the pore radii at low fluences is attributed to an increase in crystallinity induced
by the proton beam. As the total dose builds up, this effect is surpassed by chain scission and amorphization that grow at
a lower rate and cause the pore radii to increase again. 相似文献
5.
Latent damage tracks of energetic40Ar ions (18·56 MeV/u) have been recorded in Lexan polycarbonate detector. Bulk and track-etch parameters are evaluated under successive chemical
etching. Our results show a linear correlation between the measured track-etch rate along the track and the corresponding
total energy-loss rate and predict a threshold value of 5·0 MeV mg−1 cm2 for track registration. Maximum etchable track lengths of40Ar ions as a function of energies have also been measured and compared with three different sets of theoretical ranges. 相似文献
6.
Silicon crystals after implantation of erbium ions with energies in the range 0.8–2.0 MeV and doses in the range 1×1012–1×1014 cm−2 have been studied by two-and three-crystal x-ray diffraction. Three types of two-crystal reflection curves are observed.
They correspond to different structural states of the implanted layers. At moderate doses (1×1012–1×1013 cm−2) a positive strain is observed, due to the formation of secondary radiation defects of interstitial type. An increase of
the implantation dose is accompanied by the formation of an amorphous layer separating the bulk layer and a thin monocrystalline
surface layer. At an implantation dose of 1×1014 cm−2 the monocrystalline surface layer is completely amorphized. Parameters of the implantation layers are determined. A model
of the transformation of structural damage is discussed.
Fiz. Tverd. Tela (St. Petersburg) 39, 853–857 (May 1997) 相似文献
7.
J S Yadav A P Sharma G N Flerov V O Perelygin S G Stetsenko P Pellas C Perron R Antanasijevich B Jakupi Y Todorovich 《Pramana》1983,20(4):287-292
A study is made for the search of superheavy nuclei in Marjalahti, Eagle Station and in other pallasite olivines. The olivine
crystals are calibrated for heavy ion track lengths by using heavy ion beams from cyclotrons. The calibration for ultra heavy
ions which are presently not available with sufficient energy to produce volume tracks in olivine crystals, is based on Katz
and Kobetich model of track formation. The length spectrum of volume tracks, revealed by puncturing them with focussed Nd-glass
laser beam, is measured and the abundances of different nuclei groups are calculated. Partial annealing has been used at 430°C
for 32 hr which eliminates the interfering tracks due to nuclei of atomic numberS ≤ 50. During the scanning 4 cm3 olivine crystals, about 360 long tracks of uranium group as well as two very long tracks have been found. If these tracks
belong to superheavy nuclei, the relative abundance of super heavies is found to be 6 × 10−11 in galactic cosmic rays. 相似文献
8.
Raman spectroscopy was used to study the evolution of host lattice recrystallization in high-fluence N+-implanted GaAs. A high-fluence of N+ ions (>1015 cm−2) was introduced into semi-insulating GaAs by the combinatorial implantation method. Subsequent thermal annealing at 800 °C was carried out to re-grow the implantation-induced amorphous layers. The dependence of Raman parameters on N contents was systematically observed for each recrystallized cell. The volume of the newly formed crystallites with original orientation decreases with increasing fluences, whereas that of crystallites of other orientations increases after high-fluence implantation and annealing. The correlation length L, representing the size of crystalline regions with preserved translational symmetry, was determined by fitting the LO phonon signal with spatial correlation model. For 1016 cm−2 implantation, the recrystallized layer consists of nano-meter-sized crystallites (∼30 nm). The dimension of the recrystallized crystallites decreases with increasing N+ fluences, in good agreement with the model. 相似文献
9.
An x-ray diffraction study of defect formation in silicon irradiated by Kr+ (210 MeV, 8×1012−3×1014 cm−2) and Xe+ (5.6 BeV, 5×1011−5×1013 cm−2) ions is reported. It has been established that irradiation produces a defect structure in the bulk of silicon, which consists
of ion tracks whose density of material is lower than that of the host. The specific features of defect formation are discussed
taking into account the channeling of part of the ions along the previously formed tracks and the dominant role of electron
losses suffered by the high-energy ions. It is shown that the efficiency of incorporation of stable defects by irradiation
with high-energy ions is lower than that reached by implanting medium-mass ions with energies of a few hundred keV.
Fiz. Tverd. Tela (St. Petersburg) 40, 1627–1630 (September 1998) 相似文献
10.
A sequential three-dimensional (3D) particle-in-cell simulation code PICPSI-3D with a user friendly graphical user interface
(GUI) has been developed and used to study the interaction of plasma with ultrahigh intensity laser radiation. A case study
of laser–plasma-based electron acceleration has been carried out to assess the performance of this code. Simulations have
been performed for a Gaussian laser beam of peak intensity 5 × 1019 W/cm2 propagating through an underdense plasma of uniform density 1 × 1019 cm − 3, and for a Gaussian laser beam of peak intensity 1.5 × 1019 W/cm2 propagating through an underdense plasma of uniform density 3.5 × 1019 cm − 3. The electron energy spectrum has been evaluated at different time-steps during the propagation of the laser beam. When the
plasma density is 1 × 1019 cm − 3, simulations show that the electron energy spectrum forms a monoenergetic peak at ~14 MeV, with an energy spread of ±7 MeV.
On the other hand, when the plasma density is 3.5 × 1019 cm − 3, simulations show that the electron energy spectrum forms a monoenergetic peak at ~23 MeV, with an energy spread of ±7.5 MeV. 相似文献
11.
M. Takai P. H. Tsien S. C. Tsou D. Röschenthaler M. Ramin H. Ryssel I. Ruge 《Applied Physics A: Materials Science & Processing》1980,22(2):129-136
CW CO2-laser annealing of arsenic implanted silicon was investigated in comparison with thermal annealing. Ion channeling, ellipsometry,
and Hall effect measurements were performed to characterize the annealed layers and a correlation among the different methods
was made. The laser annealing was done with power densities of 100 to 640 W cm−2 for 1 to 20 s. It was found that the lattice disorder produced during implantation can be completely annealed out by laser
annealing with a power density of 500 W cm−2 and the arsenic atoms are brought on lattice sites up to 96±2%. The maximum sheet carrier concentration of 6×1015 cm−2 was obtained for 1×1016 cm−2 implantation after laser annealing, which was up to 33% higher than that after thermal annealing at 600 to 900°C for 30 min. 相似文献
12.
The magnetoelectric (ME) effect is studied in composite two- and three-layer disk structures containing magnetostriction layers
of an amorphous FeNiSiC ferromagnet and a lead zirconate titanate piezoelectric layer. Due to a high magnetostriction (∼33
× 10−6) and a low saturation field (∼200 Oe), an FeNiSiC layer has a high piezomagentic coefficient, which results in an effective
ME coupling in low fields (∼25 Oe). The ME effect is ∼0.2 V cm−1 Oe−1 at a low frequency and increases to 11.9 and 13.2 V cm−1 Oe−1 when bending and in-plane mechanical vibrations are excited in a resonance manner in the structures at frequencies of ∼8.2
and ∼170.0 kHz, respectively. Structures containing amorphous FeNiSiC layers are promising for magnetic field transducers
and electric energy generators and converters. 相似文献
13.
We report the modification of molecular beam epitaxy grown strain-relaxed single crystalline Si1−xGex layers for x=0.5 and 0.7 as a result of irradiation with 100 MeV Au ions at 80 K. The samples were structurally characterized by Rutherford backscattering spectrometry/channeling, transmission electron microscopy (TEM) and high-resolution X-ray diffraction before and after irradiation with fluences of 5×1010, 1×1011 and 1×1012 ions/cm2, respectively. No track formation was detected in both the samples from TEM studies and finally, the crystalline to amorphous phase transformation at 1×1012 ions/cm2 was examined to be higher for Si0.3Ge0.7 layers compared to Si0.5Ge0.5 layers. 相似文献
14.
P. R. Poudel B. Rout D. R. Diercks Y. M. Strzhemechny F. D. Mcdaniel 《Applied Physics A: Materials Science & Processing》2011,104(1):183-188
The β-SiC nanocrystals were synthesized by the implantation of carbon ions (C−) into silicon followed by high-temperature annealing. The carbon fluences of 1×1017, 2×1017, 5×1017, and 8×1017 atoms/cm2 were implanted at an ion energy of 65 keV. It was observed that the average size of β-SiC crystals decreased and the amount of β-SiC crystals increased with the increase in the implanted fluences when the samples were annealed at 1100 °C for 1 h. However,
it was observed that the amount of β-SiC linearly increased with the implanted fluences up to 5×1017 atoms/cm2. Above this fluence the amount of β-SiC appears to saturate. The Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and X-ray diffraction (XRD)
techniques were used to characterize the samples. 相似文献
15.
Slow positrons have been used to study ZnO layers grown on a-axis sapphire and irradiated by 2 MeV O+ ions to fluences from 1012 cm−2 to 1017 cm−2. At low fluences Zn vacancies are observed, and their introduction rate is estimated as 2000 cm−1. At the highest fluences of 1016-1017 cm−2 vacancy clusters are formed. The extent of the primary damage and its recovery is discussed. 相似文献
16.
P.?Madejczyk A.?Piotrowski K.?K?os W.?Gawron J.?Rutkowski A.?Rogalski 《Opto-Electronics Review》2010,18(3):271-276
The acceptor doping of mercury cadmium telluride (HgCdTe) layers grown by MOCVD are investigated. (111)HgCdTe layers were
grown on (100)GaAs substrates at 350°C using horizontal reactor and interdiffused multilayer process (IMP). TDMAAs and AsH3
were alternatively used as effective p-type doping precursors. Incorporation and activation rates of arsenic have been studied.
Over a wide range of Hg1−xCdxTe compositions (0.17 < x < 0.4), arsenic doping concentration in the range from 5×1015 cm−3 to 5×1017 cm−3 was obtained without postgrowth annealing. The electrical and chemical properties of epitaxial layers are specified by measurements
of SIMS profiles, Hall effect and minority carrier lifetimes. It is confirmed that the Auger-7 mechanism has decisive influence
on carrier lifetime in p-type HgCdTe epilayers. 相似文献
17.
A. V. Dvurechenskii A. A. Karanovich R. Grötzschel F. Herrmann R. Kegler A. V. Rybin 《Physics of the Solid State》1998,40(2):195-199
Electron spin resonance has been used to study the depth distribution of point defects in Si samples bombarded by N5+ (E=16 MeV) and Si5+ (E=26.8 MeV) ions at 175 and 300 K in the dose range (4–8)×1015 cm−2. It was established that unlike the implantation of moderate-energy Si ions (E ∼ 100 keV), the depth distributions of planar tetravacancies in samples bombarded by ions at 300 K under these conditions
have two maxima. The experimental results indicate that the tetravacancy density maximum closer to the surface is formed as
a result of secondary defect formation processes. No continuous amorphous layer was observed in the bulk of any of the Si
samples. This experimental observation is evidence of defect annealing which takes place when high-energy ions are implanted
in Si.
Fiz. Tverd. Tela (St. Petersburg) 40, 217–222 (February 1998) 相似文献
18.
H. Reuther 《Hyperfine Interactions》1990,56(1-4):1637-1641
Up to now a great deal of investigations in ion beam mixing of iron-aluminium layers are known. However, the easier way to
produce such layers by direct implantation of aluminium ions in iron is less studied. In the present work aluminium implanted
iron layers are studied.
Iron samples were implanted with aluminium ions at 50, 100, and 200 keV, respectively, with doses between 5×1016 and 5×1017 cm−2. Independent of energy, at doses up to 2×1017 cm−2, besides alpha iron further magnetic fractions with a Fe3Al-like structure are formed while at a dose of 5×1017 cm−2 amorphous nonmagnetic components are formed. 相似文献
19.
E. Mezzetti B. Minetti F. Abbattista M. Vallino D. Andreone V. Lacquaniti R. Cherubini 《Il Nuovo Cimento D》1990,12(7):1017-1020
Summary Pellets of sintered YBa2Cu3O7−δ with three different oxygen contents have been irradiated with fast neutron beams of energies 6.5, 3.3 and 4.4 MeV at fluences
of 7.7·104, 1.3·105 and 1.4·109 n/cm2, respectively. The radiation damage has been investigated by comparing the critical temperature (T
c
mid
), the zero resistivity and the onset temperature before and after neutron irradiation. The critical current has been measured
for a few samples in the same experimental conditions. In all transport measurements two different responses to the neutron
radiation are observed and discussed. 相似文献
20.
Oxygen isotope separation has been examined by utilizing the two-frequency infrared multiphoton dissociation (IRMPD) of 2,3-dihydropyran
(DHP). The two-frequency IRMPD reduces the required laser fluences to those lower than the damage threshold of optical windows.
For example, dissociation probability of DHP containing 18O (D(18O)) and enrichment factor (S) were obtained to be 1.6×10−3/pulse and 316, respectively, by the simultaneous irradiation with 1052.2 cm−1 photons at 0.45 J/cm2 and 1031.5 cm−1 photons at 1.06 J/cm2. These are comparable with D(18O)=2.2×10−3/pulse and S=391 obtained by the single-frequency irradiation of 1033.5 cm−1 photons at 2.2 J/cm2. Therefore, the production rate of an 18O enriched dissociation product has been increased to four times or more, compared with the single-frequency IRMPD, and this
two-frequency method would promise a practical large scale separation. 相似文献