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1.
Garima Agarwal Ankur Jain Shivani Agarwal D. Kabiraj I. P. Jain 《Bulletin of Materials Science》2006,29(2):187-191
Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. We have investigated
the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations
were undertaken at room temperature using 120 MeV Au ions at the Co/Si interface for investigation of ion beam mixing at various
doses: 8 × 1012, 5 × 1013 and 1 × 1014 cm−2. Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction (GIXRD) technique,
which shows enhancement of intermixing and silicide formation as a result of irradiation.I–V characteristics at Co/Si interface were undertaken to understand the irradiation effect on conduction mechanism at the interface. 相似文献
2.
Veenu Sisodia S. D. Dhole 《Journal of Materials Science: Materials in Electronics》2013,24(10):3634-3639
Zirconium silicide was synthesized on Si (100)/zirconium interface by means of swiftly moving 150 MeV Au ion beam. Thin films of zirconium (~60 nm) were deposited on Si (100) substrates in ultra high vacuum conditions using the electron-beam evaporation technique. The system was exposed to different ion fluencies ranging from 3 × 1013 to 1 × 1014 ions/cm2 at room temperature. Synthesized zirconium silicide thin film reasonably affects the resistivity of the irradiated system and for highest fluence of 1 × 1014 ions/cm2 resistivity value reduces from 84.3 to 36 μΩ cm. A low resistivity silicide phase, C-49 ZrSi2 was confirmed by X-ray analysis. Schottky barrier height was calculated from I–V measurements and the values drops down to 0.58 eV after irradiation at 1 × 1014 ions/cm2. The surface and interface morphologies of zirconium silicide were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM shows a considerable change in the surface structure and SEM shows the ZrSi2 agglomeration and formation of Si-rich silicide islands. 相似文献
3.
K. Vijayakumar C. Sanjeeviraja M. Jayachandran L. Amalraj 《Journal of Materials Science: Materials in Electronics》2011,22(8):929-935
Thin films of tin disulphide on glass substrates were prepared by spray pyrolysis technique using precursor solutions of SnCl2·2H2O and n–n dimethyl thiourea at different substrate temperatures varied in the range 348–423 K. Using the hot probe technique
the type of conductivity is found to be n type. X ray diffraction analysis revealed the polycrystalline nature with increasing
crystallinity with respect to substrate temperature. The preferential orientation growth of SnS2 compound having hexagonal structure along (002) plane increased with the substrate temperature. The size of the tin disulphide
crystallites with nano dimension were determined using the Full Width Half Maximum values of the Bragg peaks and found to
increase with the substrate temperature. The surface morphology had been observed on the surface of these films using scanning
electron microscope. The optical absorption and transmittance spectra have been recorded for these films in the wavelength
range 400–800 nm. Thickness of these films was found using surface roughness profilometer. The absorption coefficient (α) was determined for all the films. Direct band gap values were found to exist in all the films deposited at different substrate
temperatures. The value of room temperature resistivity in dark decreased from 5.95 × 103 Ω cm for the amorphous film deposited at low temperature (348 K) to 2.22 × 103 Ω cm for the polycrystalline film deposited at high temperature (423 K) whereas the resistivity values in light decreased
from 1.48 × 103 to 0.55 × 103 Ω cm respectively, which is determined using the four probe method. Activation energy of these thin films was determined
by Arrhenius plot. 相似文献
4.
A large number of thin films of cadmium oxide have been prepared on glass substrates by spray pyrolysis method. The prepared
films have uniform thickness varying from 200–600 nm and good adherence to the glass substrate. A systematic study has been
made on the influence of thickness on resistivity, sheet resistance, carrier concentration and mobility of the films. The
resistivity, sheet resistance, carrier concentration and mobility values varied from 1·56–5·72×10−3 Ω-cm, 128–189 Ω/□, 1·6–3·9×1021 cm−3 and 0·3–3 cm2/Vs, respectively for varying film thicknesses. A systematic increase in mobility with grain size clearly indicates the reduction
of overall scattering of charge carriers at the grain boundaries. The large concentration of charge carriers and low mobility
values have been attributed to the presence of Cd as an impurity in CdO microcrystallites. Using the optical transmission
data, the band gap was estimated and found to vary from 2·20–2·42 eV. These films have transmittance around 77% and average
reflectance is below 2·6% in the spectral range 350–850 nm. The films aren-type and polycrystalline in nature. SEM micrographs of the CdO films were taken and the films exhibit clear grains and grain
boundary formation at a substrate temperature as low as 523 K. 相似文献
5.
The electrical and optical properties of In2O3 films prepared at room temperature by activated reactive evaporation have been studied. Hall effect measurements at room
temperature show that the films have a relatively high mobility 15 cm2v−1s−1, high carrier concentration 2·97 × 1020/cm3, with a low resistivityρ = 1·35 × 10−3 ohm cm. As-prepared film is polycrystalline. It shows both direct and indirect allowed transitions with band gaps of 3·52eV
and 2·94eV respectively. 相似文献
6.
Evaporated palladium films of 45 nm thickness on Si(1 1 1) were irradiated using 78 keV Ar+ ions with doses in the range of 1×1015 to 1.5×1016 cm–2 for the purpose of studying silicide formation. Rutherford backscattering analysis shows that intermixing has occurred across the Pd-Si interface at room temperature. The mixing behaviour increases with increasing dose of the bombarding ions, which agrees well with a theoretical model of isotropic cascade mixing for palladium, and radiation-enhanced diffusion associated with an interstitial mechanism for silicon. 相似文献
7.
Shweta Agrawal Subodh Srivastava Sumit Kumar S. S. Sharma B. Tripathi M. Singh Y. K. Vijay 《Bulletin of Materials Science》2009,32(6):569-573
Semiconductor nanocrystals (NCs) have received much interest for their optical and electronic properties. When these NCs dispersed
in polymer matrix, brightness of the light emission is enhanced due to their quantum dot size. The CdCuS NCs have been synthesized
by chemical route method and then dispersed in PMMA matrix. These nanocomposite polymer films were irradiated by swift heavy
ion (SHI) (100 MeV, Si+7 ions beam) at different fluences of 1 × 1010 and 1 × 1012 ions/cm2 and then compared their structural and optical properties by XRD, atomic force microscopy, photoluminescence, and UV-Vis
spectroscopy before and after irradiation. The XRD spectra showed a broad hump around 2θ ≈ 11·83° due to amorphous PMMA and other peaks corresponding to hexagonal structure of CdS nanocrystals in PMMA matrix. The
photoluminescence spectra shows a broad peak at 530 nm corresponding to green emission due to Cu impurities in CdS. The UV-Vis
measurement showed red shift in optical absorption and bandgap changed from 4·38–3·60 eV as the irradiation fluency increased
with respect to pristine CdCuS nanocomposite polymer film. 相似文献
8.
Ap-type pseudo-binary alloy semiconductor, Pb0·3Sn0·7Te, has been prepared fromp-type specimens of PbTe and SnTe and lattice constants determined with an accuracy of 0.0001 nm. Vacuum annealing of Pb0·3Sn0·7 Te reveals two new x-ray powder diffraction lines bearing indices (444) and (800), while others become more sharp, CuKa-doublets get clearly resolved and the lattice constant is increased by ∼ 0·0002 nm. Slight deviation from Vegard’s law linearity
is observed showing that the sample must be considered as ternary in nature. Thin films deposited on mica and glass substrates
kept at room temperature are found to have a little higher SnTe content. The effective carrier concentration calculated from
Hall measurements at room temperature is ∼ 3·4×1026 m−3. 相似文献
9.
We have investigated the current–voltage (I–V) and capacitance–voltage (C–V) characteristics of Ru/Pt/n-GaN Schottky diodes in the temperature range 100–420 K. The calculated values of barrier height and ideality factor for the
Ru/Pt/n-GaN Schottky diode are 0·73 eV and 1·4 at 420 K, 0·18 eV and 4·2 at 100 K, respectively. The zero-bias barrier height (Φb0) calculated from I–V characteristics is found to be increased and the ideality factor (n) decreased with increasing temperature. Such a behaviour of Φb0 and n is attributed to Schottky barrier (SB) inhomogeneities by assuming a Gaussian distribution (GD) of barrier heights (BHs)
at the metal/semiconductor interface. The current–voltage–temperature (I–V–T) characteristics of the Ru/Pt/n-GaN Schottky diode have shown a double Gaussian distribution having mean barrier heights (
[`(F)]\textb0 {\bar{{\Phi}}_{\text{b}0}} ) of 1·001 eV and 0·4701 eV and standard deviations (σ
0) of 0·1491 V and 0·0708 V, respectively. The modified ln (J0 /T2 )-( q2s 02/2k2T2 ){ln} ({{J}_{0} /{T}^{2}} )-( {{q}^{2}{\sigma} _{0}^{2}/{2}{k}^{2}{T}^{2}} ) vs 103/T plot gives
[`(F)]\textb0 \bar{{\Phi}}_{\text{b}0} and Richardson constant values as 0·99 eV and 0·47 eV, and 27·83 and 10·29 A/cm2K2, respectively without using the temperature coefficient of the barrier height. The difference between the apparent barrier
heights (BHs) evaluated from the I–V and C–V methods has been attributed to the existence of Schottky barrier height inhomogeneities. 相似文献
10.
Polyvinyl alcohol (PVA)–polyethylene glycol (PEG) based solid polymer blend electrolytes with magnesium nitrate have been
prepared by the solution cast technique. Impedance spectroscopic technique has been used, to characterize these polymer electrolytes.
Complex impedance analysis was used to calculate bulk resistance of the polymer electrolytes. The a.c.-impedance data reveal
that the ionic conductivity of PVA–PEG–Mg(NO3)2 system is changed with the concentration of magnesium nitrate, maximum conductivity of 9·63 × 10 − 5 S/cm at room temperature was observed for the system of PVA–PEG–Mg(NO3)2 (35–35–30). However, ionic conductivity of the above system increased with the increase of temperature, and the highest conductivity
of 1·71 × 10 − 3 S/cm was observed at 100°C. The effect of ionic conductivity of polymer blend electrolytes was measured by varying the temperature
ranging from 303 to 373 K. The variation of imaginary and real parts of dielectric constant with frequency was studied. 相似文献
11.
N. A. Sobolev M. A. Oliveira R. M. Rubinger A. J. Neves M. C. Carmo V. P. Lesnikov V. V. Podolskii Y. A. Danilov E. S. Demidov G. N. Kakazei 《Journal of Superconductivity and Novel Magnetism》2007,20(6):399-403
The electrical and magnetic properties of GaSb:Mn layers deposited on (100)GaAs substrates from a laser plasma in vacuum have
been studied. It is shown that the films deposited at 200–440 °C are mosaic single crystalline and epitaxial to the substrate,
with p-type conduction. Manganese-doped layers had a hole concentration higher than 1×1019 cm−3 and fairly high values of mobility (up to 40 cm2/V s at 300 K). The layers grown at 200 °C exhibited an anomalous Hall effect up to approximately room temperature. On the
contrary, a normal Hall effect was observed in the layers grown at 440 °C. Ferromagnetic resonance measurements have revealed
the existence of ferromagnetism in the sample grown at 200 °C. The transition temperature is close to room temperature, in
full agreement with the Hall data. In the sample grown at 440 °C, the formation of ferromagnetic clusters has tentatively
been concluded. 相似文献
12.
L. D. Ivanova 《Inorganic Materials》2011,47(9):965-970
Rhenium-doped higher manganese silicide based materials have been prepared by hot pressing. It has been shown that the pressing
temperature of the materials can be lowered by adding titanium as a reductant or by sonication during pressing. The average
thermoelectric figure of merit of the materials in the temperature range 600–900 K is Z ≅ 0.7 × 10−3 K−1. 相似文献
13.
The present work deals with the mixing of metal and silicon by swift heavy ions in high-energy range. Threshold value for
the defect creation in metal Fe calculated was found to be ∼ 40 keV/nm. A thin film of Fe (10 nm) was deposited on Si (100)
at a pressure of 4 × 10−8 Torr and was irradiated with 95 MeV Au ions. Irradiation was done at RT, to a dose of 1013 ions/cm2 and 1 pna current. The electronic energy loss was found to be 29.23 keV/nm for 95 MeV Au ions in Fe using TRIM calculation.
Compositional analysis of samples was done by Rutherford backscattering spectroscopy. Reflectivity studies were carried out
on the pre-annealed and post-annealed samples to study irradiation effects. Grazing incidence X-ray diffraction was done to
study the interface. It was observed that ion beam mixing reactions at RT lead to mixing as a result of high electronic excitations. 相似文献
14.
Transparent and conducting SnO2 films are prepared at 500°C on quartz substrates by chemical vapour deposition technique, involving oxidation of SnCl2. The effect of oxygen gas flow rate on the properties of SnO2 films is reported. Oxygen with a flow rate from 0·8–1·35 lmin−1 was used as both carrier and oxidizing gas. Electrical and optical properties are studied for 150 nm thick films. The films
obtained have a resistivity between 1·72 × 10−3 and 4·95 × 10−3 ohm cm and the average transmission in the visible region ranges 86–90%. The performance of these films was checked and the
maximum figure of merit value of 2·03 × 10−3 ohm−1 was obtained with the films deposited at the flow rate of 1·16 lmin−1. 相似文献
15.
K. H. Kang H. S. Moon K. C. Song M. S. Yang S. H. Lee S. W. Kim 《International Journal of Thermophysics》2007,28(5):1595-1606
The thermal diffusivity of a simulated fuel with fission products forming a solid solution was measured using the laser-flash
method in the temperature range from room temperature to 1673 K. The density and the grain size of the simulated fuel with
the solid solutions used in the measurement were 10.49 g · cm−3 (96.9% of theoretical density) at room temperature and 9.5 μm, respectively. The diameter and thickness of the specimens were 10 and 1 mm, respectively. The thermal diffusivity decreased
from 2.108 m2 · s−1 at room temperature to 0.626 m2 · s−1 at 1673 K. The thermal conductivity was calculated by combining the thermal diffusivity with the specific heat and density.
The thermal conductivity of the simulated fuel with the dissolved fission products decreased from 4.973 W · m−1 · K−1 at 300 K to 2.02 W · m−1 · K−1 at 1673 K. The thermal conductivity of the simulated fuel was lower than that of UO2 by 34.36% at 300 K and by 15.05% at 1673 K. The difference in the thermal conductivity between the simulated fuel and UO2 was large at room temperature, and decreased with an increase in temperature.
Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5–8, 2005, Bratislava, Slovak
Republic. 相似文献
16.
Transparent conducting tin oxide thin films have been prepared by electron beam evaporation and spray pyrolysis methods. Structural,
optical and electrical properties were studied under different preparation conditions like substrate temperature, solution
flow rate and rate of deposition. Resistivity of undoped evaporated films varied from 2.65 × 10−2 ω-cm to 3.57 × 10−3 ω-cm in the temperature range 150–200°C. For undoped spray pyrolyzed films, the resistivity was observed to be in the range
1.2 × 10−1 to 1.69 × 10−2 ω-cm in the temperature range 250–370° C. Hall effect measurements indicated that the mobility as well as carrier concentration
of evaporated films were greater than that of spray deposited films. The lowest resistivity for antimony doped tin oxide film
was found to be 7.74 × 10−4 ω-cm, which was deposited at 350°C with 0.26 g of SbCl3 and 4 g of SnCl4 (SbCl3/SnCl4 = 0.065).
Evaporated films were found to be amorphous in the temperature range up to 200°C, whereas spray pyrolyzed films prepared at
substrate temperature of 300– 370°C were poly crystalline. The morphology of tin oxide films was studied using SEM. 相似文献
17.
Flexible piezo- and pyroelectric composite was made in the thin film form by spin coating. Lead Zirconate Titanate (PZT) ceramic
powder was dispersed in a castor oil-based polyurethane (PU) matrix, providing a composite with 0–3 connectivity. The dielectric
data, measured over a wide range of frequency (10–5 Hz to 105 Hz), shows a loss peak around 100 Hz related with impurities in the polymer matrix. There is also an evidence of a peak in
the range 10–4 Hz, possibly originating from the glass transition temperature Tg of the polymer. The pyroelectric coefficient at 343 K is 7.0×10–5 C·m–2·K–1 which is higher than that of β-PVDF (1×10–5 C·m–2·K–1).
Electronic Publication 相似文献
18.
C. C. Silva F. P. Filho M. F. P. Graça M. A. Valente A. S. B. Sombra 《Bulletin of Materials Science》2008,31(4):635-638
In this work we report preparation, structural and dielectric analyses of iron oxide added in hydroxyapatite bioceramic (Ca10(PO4)6(OH)2 — HAP). Hydroxyapatite is the main mineral constituent of teeth and bones with excellent biocompatibility with hard and muscle
tissues. The samples were prepared through a calcination procedure associated with dry high-energy ball milling process with
different iron concentrations (1, 2·5 and 5 wt%). The dielectric analyses were made measuring the sample impedance in the
frequency range 1 kHz–10 MHz, at room temperature. The relative permittivity of the ceramics, at 10 MHz, are between 7·13
± 0·07 (1 wt%) and 6·20 ± 0·11 (5 wt%) while e
n
are between 0·0795 ± 0·008 (1 wt%) and 0·067 ± 0·012 (5 wt%). These characteristics were related to the sample microstructures
studied by X-ray diffraction and SEM. 相似文献
19.
The room temperature diffusivity of hydrogen in a fully B2 ordered iron aluminide of composition Fe-35·8 Al was estimated
from the experimental hydrogen depth profile to be 2·38×10−15m2/s. The mathematical procedure utilized for data analysis has been described. The estimated diffusivity is a lower bound value
due to surface trapping effects. 相似文献
20.
Renato A. C. Santana Shiva Prasad Elisangela S. Moura Ana R. N. Campos Gecilio P. Silva Pedro Lima-Neto 《Journal of Materials Science》2007,42(7):2290-2296
A study to optimize the process parameters for electrodeposition of a Ni–Fe–Mo alloy is reported. A 22full factorial design was successfully employed for the experimental design analysis of the results. The optimum experimental
conditions for producing the corrosion resistant alloy were 120 mA/cm2 current density, 20 rpm cathode rotation, 9.0 pH at 30 °C. The alloy was deposited at 61% current efficiency, with an average
composition of 62 wt% Ni, 17wt% Fe, 21wt% Mo and traces of boron, and with E
corr −0.506 V, R
p
8.883 × 103 Ohm cm2 and I
corr 6.468 × 10−7 A/cm2. The deposit obtained under these conditions had an amorphous character, good adherence, high corrosion resistance and a
nodular morphology. Electrochemical corrosion tests verified that the electrodeposited Ni–Fe–Mo alloy had better corrosion
resistance than the Fe–Mo alloy. 相似文献