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1.
A study of Pentacene OTFTs using La2O3 as gate insulator is presented. The device characteristics were studied and analyzed. The OTFTs exhibit p-type conductivity with field effect mobility 6.5 × 10−8 m2/V.s, ON/OFF ratio 1.4 × 102, sub-threshold swing 2 mV/decade and hole concentration 4.5 × 1017 cm−3. The SEM and XRD analysis on the semiconductor film are also reported. 相似文献
2.
Wenwei Ge Hong Liu Xiangyong Zhao Xiaobing Li Xiaoming Pan Di Lin Haiqing Xu Xiangping Jiang Haosu Luo 《Applied Physics A: Materials Science & Processing》2009,95(3):761-767
In this paper, a single crystal of 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 with dimensions of Φ 30×10 mm was grown by the top-seeded-solution growth method. X-ray powder diffraction results show that the as-grown crystal
possesses the rhombohedral perovskite-type structure. The dielectric, piezoelectric and electrical conductivity properties
were systematically investigated with 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples. The room-temperature dielectric constants
for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples are found to be 650, 740 and 400 at 1 kHz. The (T
m, ε
m) values of the dielectric temperature spectra are almost independent of the crystal orientations; they are (306°C, 3718),
(305°C, 3613) and (307°C, 3600) at 1 kHz for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal. The optimum poling conditions were
obtained by investigating the piezoelectric constants d
33 as a function of poling temperature and poling electric field. For the 〈001〉 and 〈110〉 crystal samples, the maximum d
33 values of 146 and 117 pC/N are obtained when a poling electric field of 3.5 kV/mm and a poling temperature of 80°C were applied
during the poling process. The as-grown 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 crystal possesses a relatively large dc electrical conductivity, especially at higher temperature, having a value of 1.98×10−11 Ω−1⋅m−1 and 3.95×10−9 Ω−1⋅m−1 at 25°C and 150°C for the 〈001〉 oriented crystal sample. 相似文献
3.
In the paper the dependence of the photorefraction (PhR) in LiNbO3 and LiNbO3−Fe (0.1 wt%, 0.3wt%) crystals on light intensity (within 1016–1023 quanta·cm−2·s−1 at wavelengths 496.5 nm and 600 nm) and temperature (in the region 100–500 K) is studied. For all the crystals the limiting
values of PhR are similar and atT=293 K Δn
sat
lim
≈3·10−3. In LiNbO3 the temperature dependence of PhR in the range 100–500 K requires to take into account at least two trapping centres. 相似文献
4.
A. G. Beda V. B. Brudanin V. G. Egorov D. V. Medvedev M. V. Shirchenko A. S. Starostin 《Physics of Particles and Nuclei Letters》2010,7(6):406-409
The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant (KNPP) with the GEMMA spectrometer
is presented. Antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed at a distance
of 13.9 m from the 3 GWth reactor core is exposed to the antineutrino flux of 2.7 × 1013 cm−2 s−1. The scattered electron spectra taken in (5184 + 6798) and (1853 + 1021) h for the reactor ON and OFF periods are compared.
The upper limit for the neutrino magnetic moment μv < 3.2 × 10−11μ
B
at 90% CL is derived from the data processing. 相似文献
5.
A field-effect configuration based on La0.9Sr0.1MnO3/SrTiO3/Si structure is fabricated on Si substrate by laser molecular-beam epitaxy. The resistance modulation by electric field of
the La0.9Sr0.1MnO3/SrTiO3/Si structure is investigated in detail. An evident resistance modulation effect is observed at 80 K. The channel resistance
modulation by field effect reaches 1.4×107% and 2.6×106% when V
DS are −2 and −6.5 V, respectively. The ON/OFF ratio of approximately 4000 is obtained. The present results are worthy of further
investigations for potential applications of resistance modulation by electrostatic field in the heterostructures consisting
of perovskite oxides and Si.
Supported by the National Natural Science Foundation of China (Grant No. 50672120) and the National Basic Research Program
of China (Grant No. 2004CB619004) 相似文献
6.
Aihua Li Liang Sun Zhiren Zheng Weilong Liu Wenzhi Wu Yanqiang Yang Tianquan Lv 《Applied Physics A: Materials Science & Processing》2007,89(4):1005-1010
The results of Er3+ ion spectroscopic analysis in Sc:LiNbO3 crystals were reported. The line strengths from the ground state to the excited state were evaluated from the measured unpolarized
absorption spectrum and analyzed by using standard Judd–Ofelt theory. For Sc(3 mol. %):Er (1 mol. %):LiNbO3 crystal, the obtained intensity parameters are: Ω2=3.72×10-20 cm2, Ω4=1.07×10-20 cm2, and Ω6=0.98×10-20 cm2. The fluorescence spectra and microsecond time-resolved spectra were investigated in the visible region. The excited state
absorption transition strengths at 800 nm excitation were evaluated based on Judd–Ofelt theory. The results obtained here
were compared to results from other research on Er:LiNbO3 crystals.
PACS 71.20.Eh; 77.84.Dy; 42.70.Hj; 42.62.Fi; 42.65.Ky 相似文献
7.
R Rajesh B Ramesh Kumar S K Varshney Manoj Kumar Chhaya Chavda Aruna Thakkar N C Patel Ajai Kumar Aditya Team 《Pramana》2000,55(5-6):733-740
Thomson scattering technique based on high power laser has already proved its superoirity in measuring the electron temperature
(T
e and density (n
e) in fusion plasma devices like tokamaks. The method is a direct and unambiguous one, widely used for the localised and simultaneous
measurements of the above parameters. In Thomson scattering experiment, the light scattered by the plasma electrons is used
for the measurements. The plasma electron temperature is measured from the Doppler shifted scattered spectrum and density
from the total scattered intensity. A single point Thomson scattering system involving a Q-switched ruby laser and PMTs as the detector is deployed in ADITYA tokamak to give the plasma electron parameters. The system
is capable of providing the parameters T
e from 30 eV to 1 keV and n
e from 5 × 1012cm−3−5 × 1013cm−3. The system is also able to give the parameter profile from the plasma center (Z=0 cm) to a vertical position of Z=+22 cm to Z=−14 cm, with a spatial resolution of 1 cm on shot to shot basis. This paper discusses the initial measurements of the plasma
temperature from ADITYA. 相似文献
8.
I. Baumann R. Brinkmann M. Dinand W. Sohler L. Beckers C. Buchal M. Fleuster H. Holzbrecher H. Paulus K.-H. Müller T. Gog G. Materlik O. Witte H. Stolz W. von der Osten 《Applied Physics A: Materials Science & Processing》1996,64(1):33-44
The erbium incorporation into LiNbO3 by diffusion doping is investigated in detail by means of Secondary Ion Mass Spectrometry, Secondary Neutral Mass Spectrometry,
Rutherford Backscattering, Atomic Force Microscopy, X-ray Standing Wave technique and optical site-selective spectroscopy.
The diffusion of erbium in LiNbO3 can be described by Fick’s laws of diffusion with a concentration-independent diffusion coefficient. The diffusion constants
and activation energies for Z-cut (X-cut) LiNbO3 are 4.8×10-5 cm2/s (12.0×10-5 cm2/s) and 2.28 eV (2.44 eV), respectively. A limited solubility of erbium in LiNbO3 has to be taken into account increasing exponentially with rising temperature. During the first step of diffusion an Er
x
Nb
y
-oxide layer is formed at the surface of the sample acting as diffusion reservoir. Erbium is incorporated into LiNbO3 on vacant Li-sites slightly shifted from the original Li-position along the (-c)-direction. Site-selective spectroscopy found
four distinguishable energetically different erbium centres at this lattice site resulting from locally different symmetries
of the crystal field.
Received: 21 March 1996 / Accepted: 12 August 1996 相似文献
9.
E. I. Lakhno E. I. Burmakin I. V. Korzun G. Sh. Shekhtman 《Physics of the Solid State》2012,54(3):504-507
The rubidium monoferrite RbFeO2-based solid solutions with the composition Rb2 − 2x
Fe2 − x
P
x
O4 have been synthesized, and their crystal structure and the temperature and concentration dependences of the total and electron
conductivities have been studied. The introduction of P5+ ions has been found to sharply decrease the electron conductivity that prevails in pure rubidium monoferrite and, at the
same time, to increase the ionic conductivity. The latter becomes dominant as the phosphorus concentration increases. The
maximum rubidium-cation conductivity of the materials under study is ∼3 × 10−2 S/cm at 300°C and ∼3 × 10−1 S/cm at 700°C. The results have been compared with the previously obtained data for similar solid solutions based on rubidium
monogallate and monoaluminate. 相似文献
10.
The temperature variation of the lattice parameter of CsPbCl3 in the cubic phase has been studied by x-ray method, from a determination of the precision lattice parameter at various temperatures,
ranging from 50°C to 400°C. The coefficient of thermal expansion of CsPbCl3 can be expressed by the quadratic equation,α
T
= 21.6 × 10−6 + 2.44 × 10−9
T + 5.90 × 10−11
T
2. 相似文献
11.
A Tm, Mg co-doped LiTaO3 crystal has been grown by Czochralski method. Room temperature polarized absorption spectra and fluorescence spectrum of
the Tm, Mg:LiTaO3 crystal were measured and analyzed. The maximum absorption cross-section is 6.0791 × 10−20 cm2 at around 790 nm with full width at half maximum of 5 nm. The emission cross-section of 3
F
4 manifold was 2.2 × 10−20 cm2. The spectroscopic parameters of Tm3+ ion were calculated by applying the Judd-Ofelt approach, and the intensity parameters Ω2, Ω4, and Ω6 were obtained to be 7.71 × 10−20, 1.09 × 10−20, and 1.16 × 10−20 cm2, respectively. The branching ratios and radiative lifetimes were also presented and the radiative lifetime of Tm3+
3
F
4 → 3
H
6 transition is 968.3 μs. The results were also analyzed and compared with other Tm3+ doped hosts. 相似文献
12.
We analyzed dependence of modulation characteristics on manufacturing errors for a Y-cut Z-propagation (YZ) and an X-cut Z-propagation (XZ) LiNbO3 (LN) crystal light modulators. We investigated that the modulation of the YZ modulator is hardly affected by small rotation error of Z-axis, while the XZ modulator suffers significant influence. We also analyzed temperature characteristics of modulation of conventional temperature-compensation
LN light modulator. These numerical results show that the modulated signal change of the YZ modulator due to temperature variance is not more than 2.5% of that of the temperature-compensation modulator, in the presence
of applied electric field of integral times of the half-wave voltage, modulated signal of the YZ modulator is almost independent on the temperature. 相似文献
13.
V. V. Skobelev 《Journal of Experimental and Theoretical Physics》2010,110(2):211-219
The resonance effect of emission of axions by a hydrogen-like atom in an ultrastrong magnetic field B ≫ B
0 = m
2/e = 4.41 × 1013 Gs, which is induced by polarization of electron-positron vacuum, is considered. The emission probability and the radiation
intensity are on the order of (B/B
0) × 10−12 of electromagnetic radiation characteristics, which exceeds the conventional ratio by many orders of magnitude. It is shown
that, at the temperature of early Universe ≲(Zα)2
m, the contribution from the resonance mechanism prevails. However, the relation between the concentrations of relic photons
and axions cannot explain the origin of cold dark matter. The axion energy density in “our epoch” is 10−4(B/B
0) eV/cm3. 相似文献
14.
The field dependence of the nuclear spin-lattice relaxation (SLR) of cold implanted 82Br (T ≤ 25 mK) in α-Fe single crystals was investigated with nuclear magnetic resonance of oriented nuclei (NMR/ON) at low temperatures
as experimental technique. The SLR at the lattice sites with the hyperfine fields found by earlier NMR/ON experiments was
measured as a function of the applied external magnetic field B
ext parallel to the three principle axes [100], [110] and [111] of the iron single crystal. The data were evaluated with the
full relaxation formalism in the single impurity limit and for comparison also with the often employed model of a single exponential function with an effective relaxation time
T
1′. With a phenomenological model the high field values of the relaxation rates r
∞, [100]′ = 6.6(2) · 10−15 T2sK−1, r
∞, [110] = 5.4(2) · 10−15 T2sK−1 and r
∞, [111] = 5.2(1) · 10−15 T2sK−1 were obtained. 相似文献
15.
Neutron scattering of cold neutrons from liquid silane at 137° K and 98°K is explained on the basis of a simple model. The
rotational diffusion constant,D
r, and the delay time,τ
0, after which rotational diffusion may be said to occur are derived on the basis of this model. At 137° K we getD
r=0.22×1013 sec−1 andτ
0=0.68×10−13 sec. At 98°KD
r (=0.06×1013 sec−1) is down by a factor of more than three butτ
0=(0.54×10−13 sec) shows only a small change. By comparison with data on liquid CH4 it is concluded that the law of corresponding states is not applicable for describing rotational dynamics of CH4 and SiH4. Rotational motions in SiH4 are more hindered than in CH4 at the same reduced temperature. 相似文献
16.
The angular dependences of the electron spin resonance spectrum of 1% Ni2+ ions in a ZnSiF6·6H2O matrix are investigated experimentally at 36 GHz and 4.2 K. Besides the main spectrum of the isolated ion, we observed a
spectrum due to interacting pairs of Ni2+ ions, located in the first (nn) and second (2n) coordination spheres and coupled by, besides the magnetic dipole-dipole interaction, isotropic exchange: J
nn
= (−197±1)×10−4, J
2nα
= (−5±1)×10−4, and J
2nβ
= (3±2)×10−4 cm−1. Lines due to other isolated Ni2+ ions, which have a different initial splitting D, are also present in the spectrum with intensity comparable to the pair spectrum. Low-symmetry distortions of the crystal
field are observed, caused by a pair of impurity ions located close to one another. It is shown that the previously proposed
interpretation is incorrect.
Fiz. Tverd. Tela (St. Petersburg) 41, 1602–1608 (September 1999) 相似文献
17.
Abstract Two LiNbO3 (X and Y cut) crystals from different companies were implanted by 3.0 MeV Er ions to a dose of 7.5 × 1014 ions/cm2 and 3.5 × 1014 ions/cm2 with different beam current densities, respectively. After annealing at 1060°C in air for 2 hours, one LiNbO3 sample was implanted by 1.5 MeV He ions to a dose of 1.5 × 1016 ions/cm2. The Rutherford backscattering/channeling and prism coupling method have been used to study the damage and optical properties in implanted LiNbO3. The results show: (1) the damage in LiNbO3 created by 3.0 MeV Er ions depends strongly on the beam current density; (2) after annealing at 1060°C in air for 2 hours, a good Er doped LiNbO3 crystal was obtained; (3) there is waveguide formation possible in this Er-doped annealed LiNbO3 after 1.5 MeV He ion implantation. It is suggested that annealing is needed to remove the damage created by MeV Er ions before the MeV He ion implantation takes place, to realize the waveguide laser for Er doped LiNbO3. 相似文献
18.
The incorporation of Sn into LPE GaAs was studied as a function of the atomic fractionx
Sn
l
of Sn in the liquid (1.6×10−4≤x
Sn
l
≤0.54), the growth temperatureT
K
and the cooling rate α. The diffusion coefficient of As in Ga for moderate Sn-doping was deduced from the growth velocities
to beD
As (760° C)=(3.3±1.0)×10−5 cm2/s. The epitaxial layers were analyzed after van der Pauw with special emphasis on the sources of experimental error. With
the aid of current mobility theories the concentrations of the ionized donors and acceptors were derived. From their dependence
onx
Sn
l
, on α and onT
K
combined with the Schottky-barrier model of Sn incorporation it can be concluded that the melt and the growing crystal surface
were in thermal equilibrium. The diffusion coefficient of Sn in GaAs is about 8×10−14 cm2/s at 760° C. The distribution coefficient for Sn increases from 4.4×10−5 to 12.3×10−5 in the temperature range from 690 to 800° C. The total Sn incorporationx
Sn
s
was measured using the atomic absorption spectroscopy for the first time down tox
Sn
s
=1017/cm3. From these data it can be concluded that up tox
Sn
l
=0.54 the dopant Sn is incorporated as donor and as acceptor only and that within the experimental scatter there is no indication
of incorporation as a neutral species. 相似文献
19.
M. Takai H. Ryssel D. Röschenthaler 《Applied Physics A: Materials Science & Processing》1980,21(3):241-248
Nitrogen ions were implanted in GaAs1−xPx (x=0.4; 0.65) at room temperature at various doses from 5×1012 cm−2 to 5×1015 cm−2 and annealed at temperatures from 600°C up to 950°C using a sputtered SiO2 encapsulation to investigate the possibility of creating isoelectronic traps by ion implantation. Photoluminescence and channeling
measurements were performed to characterize implanted layers. The effects of damage induced by optically inactive neon ion
implantation on photoluminescence spectrum were also investigated. By channeling measurements it was found that damage induced
by nitrogen implantation is removed by annealing at 800°C. A nitrogen induced emission intensity comparable to the intensity
of band gap emission for unimplanted material was observed for implanted GaAs0.6P0.4 after annealing at 850°C, while an enhancement of the emission intensity by a factor of 180 as compared with an unimplanted
material was observed for implanted GaAs0.35P0.65 after annealing at 950°C. An anomalous diffusion of nitrogen atoms was found for implanted GaAs0.6P0.4 after annealing at and above 900°C. 相似文献
20.
N. N. Nikitenkov A. M. Hashhash Yu. I. Tyurin I. P. Chernov E. N. Kudryavtseva 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(3):534-537
Hydrogen permeability through diaphragms made of 12X18H12T stainless steel and Pd60Ag40 alloy under electrolytic hydrogen saturation has been studied with an electrolytic cell with a vacuum chamber. Hydrogen diffusion
constants D
H = 3.86 × 10−10 cm2 s−1 for stainless steel and D
H = 4.36 × 10−8 cm2 s−1 for Pd60Ag40 alloy have been determined at a temperature of 40°C using the Berrer relations. 相似文献