Electronic transport and structure of microcrystalline silicon deposited by the VHF-GD technique

1997 ◽  
Vol 467 ◽  
Author(s):  
M. Goerlitzer ◽  
N. Beck ◽  
P. Torres ◽  
U. Kroll ◽  
H. Keppner ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Growth Direction ◽  
Dark Conductivity ◽  
Drift Mobility ◽  
X Ray Diffraction ◽  
Microcrystalline Silicon ◽  
Direction Parallel ◽  
X Ray ◽  
Diffraction Patterns

ABSTRACTElectronic transport parallel and perpendicular to growth direction has been studied in a series of microcrystalline silicon samples obtained by various dilutions of silane in hydrogen. It is clearly shown that the transport properties (dark conductivity, drift mobility, ambipolar diffusion length and photoconductivity) under dark and under illumination conditions are enhanced as the dilution is increased. Furthermore, these films exhibit no degradation upon light-soaking. X-Ray diffraction patterns of the samples confirm that there is a correlation between the amount of crystalline fraction in the samples and the transport properties, as well as a preferential orientation along the growth direction. A similar correlation is found with the shift of the Si-H stretching mode peak of the infrared spectra (IR). Because transport properties have been measured by different techniques (dark conductivity, ambipolar length and photoconductivity in the direction perpendicular to growth direction, drift mobility in the direction parallel to growth direction), no statement can be made about a possible anisotropy in transport, as it would be expected from the columnar shape of the crystallites.

Characteristic of Raman Spectra, Crystal Structure and Superconductivity of Fe-Doped GdBa2Cu3-xFexO7-δ Systems

2011 ◽  
Vol 194-196 ◽  
pp. 1849-1853 ◽  
Author(s):  
Tao Li ◽  
Ren Zhong Xue ◽  
Chun Mei Wang ◽  
Lei Su ◽  
Hai Yang Dai ◽  
...  
Keyword(s):  
Transport Properties ◽  
Raman Spectra ◽  
Electronic Transport ◽  
Superconducting Transition ◽  
Fe Doping ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electronic Transport Properties ◽  
Diffraction Patterns ◽  
T Phase

The effects of Fe doping on the structure, electronic transport properties and Raman spectra of GdBa2Cu3-xFexO7-δ(x = 0.00-0.30) systems have been investigated. The analysis of X-ray diffraction patterns shows that the compound undergoes an Orthorhombic–Tetragonal (O-T) phase transition in the doping range of x = 0.05-0.10. The superconducting transition temperature Tc decreases with the increase of Fe doping level, whereas the superconducting transition width increases abruptly with O-T transition. We have discussed the Raman shifts and intensity of the five normal phonon peaks and some other peaks which result from the vibration of Cu(1) and O(1) oxygen for the Fe doped-samples. These investigations reveal that the electronic transport properties and Raman spectra of GdBa2Cu3-xFexO7-δcomposites obviously depend on O-T transition induced by the Fe doping.

MAGNETIC AND TRANSPORT PROPERTIES OFPr0.7Sr0.3MnO3/La0.5Ca0.5MnO3/Pr0.7Sr0.3MnO3TRILAYERS

2012 ◽  
Vol 26 (23) ◽  
pp. 1250132 ◽  
Author(s):  
H. O. WANG ◽  
P. DAI ◽  
H. LIU ◽  
W. S. TAN ◽  
F. XU ◽  
...  
Keyword(s):  
Transport Properties ◽  
Exchange Bias ◽  
Volume Fraction ◽  
Magnetic Phase ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
Metal Insulator ◽  
X Ray ◽  
Diffraction Patterns ◽  
Oriented Single Crystal

All-manganites Pr0.7Sr0.3MnO3/ La0.5Ca0.5MnO3/ Pr0.7Sr0.3MnO3(PSMO/LCMO/PSMO) trilayers were deposited on (001)-oriented single crystal MgO by pulsed laser deposition. The thickness of both PSMO layers was 36 nm while the thickness of LCMO layer varied from 6 to 36 nm. High resolution X-ray diffraction patterns indicated that trilayers were well (001)-oriented grown with high crystalline quality, and that PSMO layers were fully-strain-relaxed while LCMO spacer was partially strained. Studies on transport and magnetic properties of trilayers indicated that metal-insulator transition temperature TMIincreased from 200 K to 260 K and the saturation magnetization was suppressed with decreasing thickness of LCMO spacer from 36 to 6 nm. Transport properties of trilayers are associated with enhancement of volume fraction of ferromagnetic clusters in charge ordered and magnetic phase separated LCMO spacer. Interestingly, exchange bias (EB) was not observed in PSMO/LCMO/PSMO trilayers. It was believed that preferential distribution of metallic ferromagnetic clusters in LCMO layer may result in disappearance of EB.

Structural properties of molecular beam epitaxy grown Ni/Pt superlattices

1997 ◽  
Vol 12 (1) ◽  
pp. 161-174 ◽  
Author(s):  
W. Staiger ◽  
A. Michel ◽  
V. Pierron-Bohnes ◽  
N. Hermann ◽  
M. C. Cadeville
Keyword(s):  
Molecular Beam ◽  
Growth Direction ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Superlattice Peak ◽  
Diffraction Peaks ◽  
Diffraction Patterns

We find that the [Ni3.2nmPt1.6nm] × 15 and [Ni3.2nmPt0.8nm] × 15 multilayers are semicoherent and display a columnar morphology. From both the period of the moir’e fringes and the positions of the diffraction peaks in electronic (plan-view and crosssection geometries) and x-ray diffraction patterns, one deduces that the nickel is relaxed (at least in the error bars of all our measurements), whereas the platinum remains slightly strained (≈−1%). The interfaces are sharp; no intermixing takes place giving rise to neat contrasts in transmission electron microscopy (TEM) and to high intensities of the superlattice peaks in the growth direction in both diffraction techniques. The relaxation of the interfacial misfit occurs partially through misfit dislocations, partially through the strain of platinum. A quasiperiodic twinning occurs at the interfaces, the stacking fault which forms the twin being the most often located at the interface Pt/Ni, i.e., when a Pt layer begins to grow on the Ni layer. The simulation of the θ/2θ superlattice peak intensities takes into account the columnar microstructure. It shows that the roughness is predominantly at medium scale with a fluctuation of about 12.5% for Ni layers and negligible for Pt layers.

Effect of thermal annealing in a-InxGa1–xN films prepared by reactive RF-sputtering

2014 ◽  
Vol 92 (7/8) ◽  
pp. 943-946 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Ruichi Katayama ◽  
Shun Hibino ◽  
Yoshinori Kato ◽  
Fumitaka Ohashi ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Rf Sputtering ◽  
Large Change ◽  
Dark Conductivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radio Frequency Sputtering ◽  
Diffraction Patterns ◽  
Composition Ratios

We deposited amorphous indium gallium nitride (a-InxGa1–xN) films at room temperature by reactive radio frequency sputtering with GaN and InN targets and investigated the change of their properties from thermal annealing at annealing temperatures, Ta, below 200 °C. A large change in the indium and nitrogen composition ratios was not observed by thermal annealing at a Ta below 200 °C. In the X-ray diffraction patterns of the films annealed at a Ta below 200 °C, no perceivable peaks assigned to crystalline InxGa1–xN were found. The photoconductivty, σp, increased with an increase in Ta. On the other hand, the increase of the dark conductivity, σd, was very small with an increase in Ta below 200 °C. As a result, the photosensitivity, σp/σd, increased from 252 to 2500 by thermal annealing at a Ta of 200 °C.

Magnetic and Transport Properties of Nanostructured Sr2Fe1-Xcrxmoo6 Double Perovskite Compounds

2012 ◽  
Vol 529 ◽  
pp. 19-22
Author(s):  
Xiang Hu Li ◽  
Dan Li ◽  
Dong Wu Xiao
Keyword(s):  
Transport Properties ◽  
Sol Gel ◽  
Double Perovskite ◽  
Ferromagnetic Transition ◽  
X Ray Diffraction ◽  
Nanometer Range ◽  
Gel Method ◽  
X Ray ◽  
Diffraction Patterns ◽  
Fe Substitution

The compounds of Fe substitution of Cr in nanotructured Sr2Fe1-xCrxMoO6 (0≤x≤0.2) double perovskite have been prepared by sol-gel method. And the x-ray diffraction patterns of the samples show that the samples are in nanometer range. All the samples show a paramagnetic to ferromagnetic transition with temperature, and the Curie temprature increase with the increasing of x. The resistivity of the samples decrease with the increasing of temprature, and increase with the increasing of x.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Material Structure of Microcrystalline Silicon Deposited with an Expanding Thermal Plasma

2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij
Keyword(s):  
Thermal Plasma ◽  
Hydrogen Plasma ◽  
Plasma Chemistry ◽  
Plasma Source ◽  
Growth Direction ◽  
Interaction Time ◽  
Material Structure ◽  
Average Particle ◽  
Microcrystalline Silicon ◽  
X Ray

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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