共查询到20条相似文献,搜索用时 62 毫秒
1.
T. Kamiya A. Suemasu T. Watanabe T. Sameshima I. Shimizu 《Applied Physics A: Materials Science & Processing》2001,73(2):151-159
The carrier transport property of polycrystalline silicon (poly-Si:H:F) thin films was studied in relation to film microstructure,
impurity, in situ or post-annealing treatments to obtain better carrier transport properties. Poly-Si:H:F films were prepared
from SiF4 and H2 gas mixtures at temperatures <300 °C. Dark conductivity of the films prepared at high SiF4/H2 gas flow ratio (e.g., 60/3 sccm) exhibits a high value for intrinsic silicon and its Fermi level is located near the conduction
band edge. The carrier incorporation is suppressed well, either by in situ hydrogen plasma treatment or by post-annealing
with high-pressure hot-H2O vapor. It is confirmed that weak-bonded hydrogen atoms are removed by the hot-H2O vapor annealing. In addition, evident correlation between impurity concentrations and dark conductivity is not found for
these films. It is thought that the carrier incorporation in the films prepared at high SiF4/H2 gas flow ratios is related to grain-boundary defects such as weak-bonded hydrogen. By applying hot-H2O vapor annealing at 310 °C to a 1-μm-thick p-doped (400)-oriented poly-Si:H:F film, Hall mobility was improved from 10 cm2/Vs to 17 cm2/Vs.
Received: 7 August 2000 / Accepted: 2 March 2001 / Published online: 20 June 2001 相似文献
2.
T. Sameshima K. Sakamoto K. Asada 《Applied Physics A: Materials Science & Processing》1999,69(2):221-224
Heat treatment with high-pressure H2O vapor was applied to improve interface properties of SiO2/Si and passivate the silicon surface. Heat treatment at 180–420 °C with high-pressure H2O vapor changed SiOx films, 150 nm thick formed at room temperature by thermal evaporation in vacuum, into SiO2 films with a Si-O-Si bonding network similar to that of thermally grown SiO2 films. Heat treatment at 130 °C with 2.8×105 Pa H2O for 3 h reduced the recombination velocity for the electron minority carriers from 405 cm/s (as-fabricated 150-nm-thick
SiOx/Si) to 5 cm/s. Field-effect passivation was demonstrated by an additional deposition of defective SiOx films on the SiO2 films formed by heat treatment at 340 °C with high-pressure H2O vapor. The SiOx deposition reduced the recombination velocity from 100 cm/s to 48 cm/s.
Received: 1 March 1999 / Accepted: 28 March 1999 / Published online: 24 June 1999 相似文献
3.
L. Pintilie I. Pintilie D. Petre T. Botila M. Alexe 《Applied Physics A: Materials Science & Processing》1999,69(1):105-109
Thermally stimulated current (TSC) measurements performed in the 100 K–400 K temperature range on Bi4Ti3O12 (BiT) thin films annealed at 550 °C and 700 °C had revealed two trapping levels having activation energies of 0.55 eV and
0.6 eV. The total trap concentration was estimated at 1015 cm−3 for the samples annealed at 550 °C and 3×1015 cm−3 for a 700 °C annealing and the trap capture cross-section was estimated about 10−18 cm2. From the temperature dependence of the dark current in the temperature range 20 °C–120 °C the conduction mechanism activation
energy was found to be about 0.956–0.978 eV. The electrical conductivity depends not only on the sample annealing temperature
but also whether the measurement is performed in vacuum or air. The results on the dark conductivity are discussed considering
the influence of oxygen atoms and oxygen vacancies.
Received: 28 January 1998 / Accepted: 8 January 1999 / Published online: 5 May 1999 相似文献
4.
R.A. Gunasekaran J.D. Pedarnig M. Dinescu 《Applied Physics A: Materials Science & Processing》1999,69(6):621-624
A parametric study of the growth of La0.5Sr0.5CoO3 (LSCO) thin films on (100) MgO substrates by pulsed-laser deposition (PLD) is reported. Films are grown under a wide range
of substrate temperature (450–800 °C), oxygen pressure (0.1–0.9 mbar), and incident laser fluence (0.8–2.6 J/cm2). The optimum ranges of temperature, oxygen pressure, and laser fluence to produce c-axis oriented films with smooth surface morphology and high metallic conductivity are identified. Films deposited at low
temperature (500 °C) and post-annealed in situ at higher temperatures (600–800 °C) are also investigated with respect to their
structure, surface morphology, and electrical conductivity.
Received: 20 November 1998 / Accepted: 6 July 1999 / Published online: 21 October 1999 相似文献
5.
Matthew C. Hales Ray L. Frost Wayde N. Martens 《Journal of Raman spectroscopy : JRS》2008,39(9):1141-1149
Pure nesquehonite (MgCO3·3H2O)/Mg(HCO3)(OH)·2H2O was synthesised and characterised by a combination of thermo‐Raman spectroscopy and thermogravimetry with evolved gas analysis. Thermo‐Raman spectroscopy shows an intense band at 1098 cm−1, which shifts to 1105 cm−1 at 450 °C, assigned to the ν1CO32− symmetric stretching mode. Two bands at 1419 and 1509 cm−1 assigned to the ν3 antisymmetric stretching mode shift to 1434 and 1504 cm−1 at 175 °C. Two new peaks at 1385 and 1405 cm−1 observed at temperatures higher than 175 °C are assigned to the antisymmetric stretching modes of the (HCO3)− units. Throughout all the thermo‐Raman spectra, a band at 3550 cm−1 is attributed to the stretching vibration of OH units. Raman bands at 3124, 3295 and 3423 cm−1 are assigned to water stretching vibrations. The intensity of these bands is lost by 175 °C. The Raman spectra were in harmony with the thermal analysis data. This research has defined the thermal stability of one of the hydrous carbonates, namely nesquehonite. Thermo‐Raman spectroscopy enables the thermal stability of the mineral nesquehonite to be defined, and, further, the changes in the formula of nesquehonite with temperature change can be defined. Indeed, Raman spectroscopy enables the formula of nesquehonite to be better defined as Mg(OH)(HCO3)·2H2O. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
The adsorption of hydrogen on Pt (100) was investigated by utilizing LEED, Auger electron spectroscopy and flash desorption mass spectrometry. No new LEED structures were found during the adsorption of hydrogen. One desorption peak was detected by flash desorption with a desorption maximum at 160 °C. Quantitative evaluation of the flash desorption spectra yields a saturation coverage of 4.6 × 1014 atoms/cm2 at room temperature with an initial sticking probability of 0.17. Second order desorption kinetics was observed and a desorption energy of 15–16 kcal/mole has been deduced. The shapes of the flash desorption spectra are discussed in terms of lateral interactions in the adsorbate and of the existence of two substates at the surface. The reaction between hydrogen and oxygen on Pt (100) has been investigated by monitoring the reaction product H2O in a mass spectrometer. The temperature dependence of the reaction proved to be complex and different reaction mechanisms might be dominant at different temperatures. Oxygen excess in the gas phase inhibits the reaction by blocking reactive surface sites. At least two adsorption states of H2O have to be considered on Pt (100). Desorption from the prevailing low energy state occurs below room temperature. Flash desorption spectra of strongly bound H2O coadsorbed with hydrogen and oxygen have been obtained with desorption maxima at 190 °C and 340 °C. 相似文献
7.
Production and characterization of Nd,Cr:GSGG thin films on Si(001) grown by pulsed laser ablation 总被引:2,自引:0,他引:2
P.R. Willmott P. Manoravi K. Holliday 《Applied Physics A: Materials Science & Processing》2000,70(4):425-429
Nd,Cr:Gd3Sc2Ga3O12 (GSGG) thin films have been produced for the first time. They were grown on Si(001) substrates at 650 °C by pulsed laser
ablation at 248 nm of a crystalline Nd,Cr:GSGG target rod. The laser plume was analyzed using time-of-flight quadrupole mass
spectroscopy, and consisted of elemental and metal oxide fragments with kinetic energies typically in the range 10 to 40 eV,
though extending up to 100 eV. Although films deposited in vacuum using laser fluences of 0.8±0.1 J cm−2 reproduced the Nd,Cr:GSGG bulk stoichiometry, those deposited using fluences above ≈3 J cm−2 resulted in noncongruent material transfer and were deficient in Ga and Cr. Attempts to grow films using synchronized oxygen
or oxygen/argon pulses yielded mixed oxide phases. Under optimal growth conditions, the films were heteroepitaxial, with GSGG(001)[100]∥Si(001)[100],
and exhibited Volmer–Weber-type growth. Room-temperature emission spectra of the films suggest efficient non-radiative energy
transfer between Cr3+ and Nd3+ ions, similar to that of the bulk crystal.
Received: 1 October 1999 / Accepted: 15 October 1999 / Published online: 23 February 2000 相似文献
8.
Zirconium oxide layers have been successfully deposited by photo-CVD at low temperatures. ZrO2 growth was observed at temperatures as low as 100 °C. When deposited at 250 °C and above, these films exhibited a polycrystalline
structure with a mixture of different crystal phases. Deposition at 300 °C was found to form moisture-free ZrO2 films with a high refractive index of 2.1, a very low effective density of trapped electrons of ∼8.8×108 cm-2 and an interface trap density of 6.6×109 cm-2 eV-1 being readily obtained.
Received: 17 December 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002 相似文献
9.
A structural study of the different stages during NiO(100) sulphurization by H2S was carried out by RHEED, LEED and AES. On exposure to H2S (PH2S < 10?5 Torr) The “clean” surface, obtained by UHV cleavage, was found to react with H2S to produce islands of Ni(100) covered with an ordered c(2 × 2) S structure up to 300°C. Growth of Ni3S2 islands occurs on increasing the temperature and the exposure to H2S. 相似文献
10.
Y. Li C. Tan Y. Xia J. Zhang C. Xue H. Xu P. Liu 《Applied Physics A: Materials Science & Processing》2000,71(6):689-693
Si crystals were implanted with 2.0- MeV Er+ at the doses of 5×1012 ions/cm2, 1×1014 ions/cm2, 5×1014ions/cm2, 1×1015 ions/cm2 and 2.5×1015 ions/cm2. Conventional furnace thermal annealing was carried out in the temperature range from 600 °C to 1150 °C. The depth distribution
of Er, associated damage profiles and annealing behavioar were investigated using the Rutherford backscattering spectrometry
and channelling (RBS/C) technique. A proper convolution program was used to extract the distribution of Er from the experimental
RBS spectrum. The obtained distribution parameters, projected range Rp, projected range straggling ΔRp and skewness SK were compared with those of TRIM96 calculation.The experimental Rp and SK values agree well with the simulated values, while the experimental ΔRp is larger than TRIM 96 simulated value by a factor of 18%. The damage profile of silicon crystal induced by 2.0-MeV Er+ at a dose of 1×1014 ions/cm2 was extracted using the multiple-scattering dechannelling model based on Feldman’s method, which is in a good agreement with
the TRIM96 calculation. For the samples with dose of 5×1014 ions/cm2 and more, an abnormal annealing behavioar was found and a qualitative explaination has been given.
Received: 11 October 1999 / Accepted: 28 March 2000 / Published online: 5 July 2000 相似文献
11.
Solid oxide fuel cells directly convert the chemical energy of a fuel into electricity. To enhance the efficiency of the fuel
cells, the thickness of the gastight solid electrolyte membranes should be as thin as possible.
Y2O3-stabilised ZrO2 (YSZ) electrolyte films were prepared by reactive sputtering deposition using Zr/Y targets in Ar/O2 atmospheres. The films were 5 – 8 μm thin and were deposited onto anode substrates made of a NiO/YSZ composite. After deposition
of a cathode with the composition La0.65Sr0.35MnO3 the electrochemical properties of such a fuel cell were tested under operating conditions at temperatures between 600 °C
and 850 °C. Current-voltage curves were recorded and impedance measurements were performed to calculate apparent activation
energies from the fitted resistance data. The conductivity of the YSZ films varied between 4.6·10−6 S/cm and 2.2·10−5 S/cm at 400 °C and the fuel cell gave a reasonable power density of 0.4 W/cm2 at 0.7 V and 790 °C using H2 with 3 % H2O as fuel gas. The gas compositions were varied to distinguish the electrochemical processes of the anode and cathode in the
impedance spectra.
Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16–22, 2001. 相似文献
12.
Ce0.9Sr0.1Cr0.5Co0.5O3?δ (CSCrCo) as an anode catalyst was studied in a solid oxide fuel cell (SOFC), where hydrogen sulfide (H2S) was used as fuel. The conductivities were evaluated with a four-probe DC technique in 3 % H2-N2 and 5 % H2S-N2 at 570–800 °C, respectively. X-ray diffraction (XRD) patterns show that CSCrCo powders are fluorite structure which is similar to that of CeO2 parent (JCPDS card no. 34-0394). Meanwhile, CSCrCo anode material has good chemical compatibility with electrolyte (Ce0.8Sm0.2O1.9 (SDC)) in N2. Through the analysis of XRD and Fourier transform infrared patterns, no other new phase is detected after treatment in 5 % H2S-N2 at 800 °C for 5 h, which indicate that the material has a good sulfur tolerance. H2 temperature-programmed reduction and Tafel curves indicate that the temperature of the best catalytic activity is 600 °C. The electrochemical properties of the cell comprising CSCrCo-SDC/SDC/Ag are measured in 5 % H2S-N2 at low temperatures (500 and 600 °C). The maximal open circuit voltage is 1.04 V, the maximal power density is 12.55 mW cm?2, and the maximal current density is 40 mA cm?2 at 500 °C. While at 600 °C, the corresponding values are 0.95 V, 14.21 mW cm?2, and 90.01 mA cm?2, respectively. After SOFC operating in 5 % H2S, X-ray photoelectron spectroscopy is used to compare the fresh sample with the H2S-treated one. 相似文献
13.
S. C. Mailley A. Kelaidopoulou A. Siddle A. L. Dicks P. Holtappels C. E. Hatchwell M. Mogensen 《Ionics》2000,6(5-6):331-339
Mixed conducting oxide anodes are being considered for the direct utilisation of natural gas in high temperature fuel cells.
This work refers to the electrochemical characterization of the pyrochlore Gd2Ti0.6Mo1.2Sc0.2O7-δ (GTMS) as anode in a solid oxide fuel cell running in low humidity hydrogen or methane.
The electro-oxidation reaction was investigated using impedance spectroscopy, potentiostatic measurements and cyclic voltammetry.
Kinetic data were obtained for different fuels in the temperature range 845–932 °C. In a methane-fuelled cell, steam reforming
appears to be the rate-limiting step. The overall polarisation resistance of the anode under open circuit conditions at 932
°C was 6.86 Ω·cm2 in 97% H2/3% H2O, and 43 Ω·cm2 in 97% CH4/3% H2O. For a 97% fuel-3% H2O/GTMS//YSZ-Al2O3//Pt/air cell, the maximum power output at 932 °C was 9.5 mW/cm2 and 1.8 mW/cm2 in hydrogen and methane, respectively. First investigations on this type of electrode material show unidentified peaks on
XRD spectra after electrochemical test, which indicate GTMS instability under experimental conditions.
Paper presented at the 7th Euroconference on Ionics, Calcatoggio, Corsica, France, Oct. 1–7, 2000. 相似文献
14.
K.Y. Lim Y.S. Lee Y.D. Chung I.W. Lyo C.N. Whang J.Y. Won H.J. Kang 《Applied Physics A: Materials Science & Processing》2000,70(4):431-434
In this study, the grain boundary diffusion of Cu through a TiN layer with columnar structure was investigated by X-ray photoelectron
spectroscopy (XPS). It was observed that Cu atoms diffuse from the Cu layer to the surface along the grain boundaries in the
TiN layer at elevated temperature. In order to estimate the grain boundary diffusion constants, we used the surface accumulation
method. The diffusivity of Cu through TiN layer with columnar structure from 400 °C to 650 °C is Db≈6×10−11exp(−0.29/(kBT )) cm2/s.
Received: 18 May 1999 / Accepted: 8 September 1999 / Published online: 23 February 2000 相似文献
15.
《Current Applied Physics》2015,15(5):588-598
Thin films of tin sulphide (SnS) have been grown by sulphurization of sputtered tin precursor layers in a closed chamber. The effect of sulphurization temperature (Ts) that varied in the range of 150–450 °C for a fixed sulphurization time of 120 min on SnS film was studied through various characterization techniques. X-ray photoelectron spectroscopy analysis demonstrated the transformation of metallic tin layers into SnS single phase for Ts between 300 °C and 350 °C. The X-ray diffraction measurements indicated that all the grown films had the (111) crystal plane as the preferred orientation and exhibited orthorhombic crystal structure. Raman analysis showed modes at 95 cm−1, 189 cm−1 and 218 cm−1 are related to the Ag mode of SnS. AFM images revealed a granular change in the grain growth with the increase of Ts. The optical energy band gap values were estimated using the transmittance spectra and found to be varied from 1.2 eV to 1.6 eV with Ts. The Hall effect measurements showed that all the films were p-type conducting nature and the layers grown at 350 °C showed a low electrical resistivity of 64 Ω-cm, a net carrier concentration of 2 × 1016 cm−3 and mobility of 41 cm2 V−1 s−1. With the use of sprayed Zn0.76Mg0.24O as a buffer layer and the sputtered ZnO:Al as window layer, the SnS based thin film solar cell was developed that showed a conversion efficiency of 2.02%. 相似文献
16.
This paper reports that the Raman spectra have been recorded on the
metal-organic chemical vapour deposition epitaxially grown GaN
before and after the Mn ions implanted. Several Raman defect modes
have emerged from the implanted samples. The structures around
182 cm-1 modes are attributed to the disorder-activated Raman scattering, whereas the 361 cm-1 and 660 cm-1 peaks are assigned to nitrogen vacancy-related defect scattering. One additional peak at 280 cm-1 is attributed to the vibrational mode of gallium vacancy-related defects and/or to disorder activated Raman scattering. A Raman-scattering study of lattice recovery is also presented by rapid thermal annealing at
different temperatures between 700 °C and 1050 °C on Mn implanted GaN epilayers. The behaviour of peak-shape change and
full width at half maximum (FWHM) of the A1(LO) (733 cm-1) and EH2 (566 cm-1) Raman modes are explained on the basis of implantation-induced lattice damage in GaN epilayers. 相似文献
17.
Oxygen plasma and high pressure H2O vapor heat treatment were applied to fabrication of n-channel polycrystalline silicon thin film transistors (poly-Si TFTs).
13.56 MHz-oxygen-plasma treatment at 250 °C, 100 W for 5 min effectively reduced defect states of 25-nm-thick silicon films
crystallized by 30 ns-pulsed XeCl excimer laser irradiation. 1.3×106-Pa-H2O vapor heat treatment at 260 °C for 3 h was carried out in order to improve electrical properties of SiOx gate insulators and SiOx/Si interfaces. A carrier mobility of 470 cm2/V s and a low threshold voltage of 1.8 V were achieved for TFTs fabricated with crystallization at 285 mJ/cm2.
Received: 18 November 2002 / Accepted: 25 November 2002 / Published online: 11 April 2003
RID="*"
ID="*"Corresponding author. Fax: +81-42/388-7109, E-mail: tsamesim@cc.tuat.ac.jp 相似文献
18.
X.J. Wu D.Z. Shen K.W. Liu B.H. Li Y.M. Lu B. Yao X.W. Fan 《Solid State Communications》2007,141(6):344-347
Fe-based cadmium sulfide alloy thin films have been grown on c-plane sapphire substrates by a low-pressure metalorganic chemical vapor deposition technique at different growth temperatures. From X-ray diffraction and absorption spectra of the samples, the evolutions with growth temperature show an inflexion at the growth temperature of 300 °C. This was attributed to the phase transformation from zinc-blende to wurtzite. With increasing growth temperature from 270 °C to 360 °C, Fe concentration in the films increases monotonously. The electronic states of Cd1−xFexS were investigated by X-ray photoelectron spectroscopy. Magnetic measurement shows Van Vleck paramagnetism of the Cd1−xFexS thin film in the temperature region below 7 K. 相似文献
19.
G. Franzò V. Vinciguerra F. Priolo 《Applied Physics A: Materials Science & Processing》1999,69(1):3-12
A detailed investigation on the excitation mechanisms of rare-earth (RE) ions introduced in Si nanocrystals (nc) is reported.
Silicon nanocrystals were produced by high-dose 80-keV Si implantation in thermally grown SiO2 followed by 1100 °C annealing for 1 h. Subsequently some of the samples were implanted by 300-keV Er, Yb, Nd, or Tm at doses
in the range 2×1012–3×1015 /cm2. The energy was chosen in such a way to locate the RE ions at the same depth where nanocrystals are. Finally an annealing
at 900 °C for 5 min was performed in order to eliminate the implantation damage. These samples show intense room-temperature
luminescence due to internal 4f shell transitions within the RE ions. For instance, luminescence at 1.54 μm and 0.98 μm is
observed in Er-doped nc, at 0.98 μm in Yb-doped nc, at 0.92 μm in nc and two lines at 0.78 μm and 1.65 μm in Tm-doped nc.
Furthermore, these signals are much more intense than those observed when RE ions are introduced in pure SiO2 in the absence of nanocrystals, demonstrating the important role of nanocrystals in efficiently exciting the REs. It is shown
that the intense nc-related luminescence at around 0.85 μm decreases with increasing RE concentration and the energy is preferentially
transferred from excitons in the nc to the RE ions which, subsequently, emit radiatively. The exact mechanism of energy transfer
has been studied in detail by excitation spectroscopy measurements and time-resolved photoluminescence. On the basis of the
obtained results a plausible phenomenological model for the energy transfer mechanism emerges. The pumping laser generates
excitons within the Si nanocrystals. Excitons confined in the nc can either give their energy to an intrinsic luminescent
center emitting at around 0.85 μm nor pass this energy to the RE 4f shell, thus exciting the ion. The shape of the luminescence
spectra suggests that excited rare-earth ions are not incorporated within the nanocrystals and the energy is transferred at
a distance while they are embedded within SiO2. Rare-earth excitation can quantitatively be described by an effective cross section σeff taking into account all the intermediate steps leading to excitation. We have directly measured σeff for Er in Si nc obtaining a value of ≈2×10−17 cm2. This value is much higher than the cross section for excitation through direct photon absorption (8×10−21 cm2) demonstrating that this process is extremely efficient. Furthermore, the non-radiative decay processes typically limiting
rare-earth luminescence in Si (namely back-transfer and Auger) are demonstrated to be absent in Si nc further improving the
overall efficiency of the process. These data are reported and their implications.
Received: 9 April 1999 / Accepted: 10 April 1999 / Published online: 2 June 1999 相似文献
20.
《Solid State Ionics》1988,26(3):229-235
Amorphous LiZr2(PO4)3 has been prepared at room temperature starting from aqueous solutions of ZrOCl2, H3PO4, and LiOH and then crystallized by heating at temperatures between 600 and 900°C. The material obtained at 900°C has been characterized by X-ray powder diffractometry, DSC analysis, and ac conductivity. It is monoclinic from 20 up to about 300°C and orthorhombic at higher temperatures. A change in the activation energy for conduction (from 0.79 to 0.43 eV) and a weak endothermic effect (0.9–1.7 cal/g) are associated with the phase transition. The ac conductivity of sintered pellets is, on average, 7×10−4 S cm−1 at 300°C. 相似文献