Laser-Induced Voltages at Room Temperature in YBa2Cu3O7 and PrxY1-xBa2Cu3O7 Thin Films

1995 ◽  
Vol 397 ◽  
Author(s):  
H.- U. Habermeier ◽  
N. Jisrawi ◽  
G. Jäger-Waldau ◽  
U. Sticher ◽  
B. Leibold
Keyword(s):  
Thin Films ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Tilt Angle ◽  
Material Properties ◽  
Defect Structure ◽  
Room Temperature ◽  
Substrate Surface ◽  
Doping Dependence ◽  
Photon Fluence

ABSTRACTRecent reports on high transient transverse voltages at room temperature in YBa2Cu3O7 and PrxYl-xBa2Cu3O7 thin films grown on SrTiO3 single crystal substrates, with a tilt angle between the [ 001 ] cubic axis and the substrate surface plane, have been interpreted by thermoelectric fields transverse to a laser-induced temperature gradient which are caused by the non-zero off diagonal elements of the Seebeck tensor. We have studied this effect in epitaxially grown Pr- doped, as well as undoped YBa2Cu3O7, thin films and observed for a 2 mm long YBa2Cu3O7 strip exposed to a UV photon fluence of 100 mJ/cm2 signals as large as 30 V. The unexpected high values for the signals and their doping dependence are discussed within the frame of a model based on a thermopile arrangement, the growth induced defect structure and the doping induced modifications of the material properties.

Water Molecule Dispositions in the Cesium Sulfate α- and β-Alums: Single-Crystal Neutron Diffraction Studies of CsM(SO4)2.12H2O (M=V, Rh)

1993 ◽  
Vol 46 (9) ◽  
pp. 1337 ◽  
Author(s):  
JK Beattie ◽  
SP Best ◽  
FH Moore ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Neutron Diffraction ◽  
Water Molecule ◽  
Single Crystal ◽  
Tilt Angle ◽  
Room Temperature ◽  
Bond Angle ◽  
Sulfate Salt ◽  
Cell Dimensions ◽  
Coordinated Water ◽  
Unit Cell Dimensions

Room-temperature single-crystal neutron diffraction studies are recorded for two alums, Cs( Rh /V)(SO4)2.12H2O [cubic, Pa3, a 12.357(5) ( Rh ), 12.434(1)Ǻ (V)], residuals 0.037 and 0.068 for 328 and 164 'observed' reflections, with the intention of defining water molecule hydrogen atom orientations. Whereas the two tervalent hexaaqua cations are similar in size [ rM -O = 2.010(6)Ǻ (M = V) and 2.006(2)Ǻ (M = Rh )] the vanadium salt adopts the β alum modification while rhodium gives an α alum. Significantly, the water coordination geometry is different in the two cases with the tilt angle between the plane of the water molecule and the M-O bond vector being 1° (M = V) and 35° (M = Rh ). The tilt angle for water coordinated to rhodium in CsRh (SeO4)2.12H2O is inferred from the unit cell dimensions to be similar to that of the corresponding sulfate salt and not that which generally pertains for caesium selenate alums. Significant differences in the H-O-H bond angle are found for trigonal planar and trigonal pyramidal water coordination, suggesting that differences in the metal(III)-water interaction are a determinant of the geometry of the coordinated water molecule in the caesium sulfate/ selenate alum lattices.

AFM Study of Surface Morphology of Aluminum Nitride Thin Films

1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Ion Beam ◽  
Soda Lime ◽  
Silicon Single Crystal ◽  
Soda Lime Glass ◽  
Average Roughness

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.

Transport Studies in Single-Crystal Films of Cosi2 and Nisi2

1983 ◽  
Vol 25 ◽  
Author(s):  
J. C. Hensel ◽  
R. T. Tung ◽  
J. M. Poate ◽  
F. C. Unterwald ◽  
D. C. Jacobson
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Room Temperature Resistivity ◽  
Transport Studies ◽  
Single Crystal Films ◽  
Crystal Films ◽  
The Difference ◽  
Temperature Resistivity

ABSTRACTTransport studies have been performed on thin films of CoSi 2 and NiSis2 in the temperature range 1 to 300 K. The conductivities are metallic with essentially the same temperature dependence; however, the residual resistivities are markedly different even though the two silicides are structurally similar (the room temperature resistivity of NiSi2 being at least twice that of CoSi2 of 15 μΩ cm). The difference is attributed to intrinsic defects in NiSi2. This defect has been simulated by ion bombardment of the film where it is also shown that Matthiesen's rule is obeyed over a remarkable range of bombardment doses.

Defect structure in Co-W thin films

1986 ◽  
Vol 44 ◽  
pp. 822-823
Author(s):  
U. Admon ◽  
M.P Dariel ◽  
E. Grünbaum ◽  
G. Kimmel
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Diffraction Pattern ◽  
Orientation Relationship ◽  
Defect Structure ◽  
Substrate Surface ◽  
Stacking Faults ◽  
Deposition Process ◽  
Polycrystalline Copper ◽  
Small Grains

Thin films of Co-W, 300-500Å thick, electrodeposited unto polycrystalline copper substrates (the details of the deposition process are given in ref. 1), consist of a background of small grains of size of the order of the film thickness, in which 10-20 times larger grains are dispersed. These large grains display a predominant [0001]hcp or [001] or [lll]fcc texture. The large grains are mostly faulted, the faults appearing as parallel stripes running across their whole width (Fig. 1). These stripes have been identified by SAD and DF as being alternating hep and fee platelets. The diffraction pattern (Fig. 2), taken from grain A in Fig.1, indicates a (0001)h||(001)c||substrate surface, with [1010]h||[110]c orientation relationship between the hep and fee platelets (relationship I). The streaking and the appearance of the {200} cubic spots as cross shaped satellites is attributed to the presence of stacking faults on the {111} planes.

Growth of Au on A Ge (111) Surface

1991 ◽  
Vol 237 ◽  
Author(s):  
D. N. Dunn ◽  
P. Xu ◽  
L. D. Marks
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
High Temperatures ◽  
Room Temperature ◽  
Annealing Behavior ◽  
Temperature Growth ◽  
Au Thin Films

ABSTRACTWe investigate the room temperature growth of evaporated Au thin films on both clean and dirty single crystal Ge (111) substrates. The annealing behavior of these films was then examined under low and high temperatures.

Epitaxy, microstructure, and processing-structure relationships of TiO2 thin films grown on sapphire (0001) by MOCVD

1993 ◽  
Vol 8 (10) ◽  
pp. 2634-2643 ◽  
Author(s):  
H.L.M. Chang ◽  
T.J. Zhang ◽  
H. Zhang ◽  
J. Guo ◽  
H.K. Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Growth Parameters ◽  
Substrate Surface ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Tio2 Thin Films ◽  
Growth Plane ◽  
Deposited Films

TiO2 thin films have been deposited on sapphire (0001) substrates under various conditions by metal-organic chemical vapor deposition. The structural properties of the deposited films were characterized by x-ray diffraction and transmission electron microscopy. The important growth parameters were found to be the deposition temperature and the deposition rate. The ranges studied for the two parameters were 400 to 850 °C and 10 to 120 Å/min, respectively. Depending on the growth conditions, most of the deposited films were either single-phase anatase or rutile, or a mixture of the two. These films were all epitaxial, but none of them were single-crystal films. Three distinct epitaxial relationships were observed between the films and the substrates, and, depending on the growth conditions, a deposited film can contain one, two, or all three of them. The fact that the films we obtained, although epitaxial, were never single crystal is explained based on the consideration of the difference in the rotational symmetries of the substrate surface and the film growth plane. We believe that it should be generally true that, in heteroepitaxial growth, a true single-crystal film can never be obtained as long as the point symmetry group of the substrate surface is not a subgroup of that of the film growth plane.

Zinc Oxide Thin Films Deposited by RF Magnetron Sputtering on Mylar Substrates at Room Temperature

2001 ◽  
Vol 685 ◽  
Author(s):  
Elvira Fortunato ◽  
Patrícia Nunes ◽  
António Marques ◽  
Daniel Costa ◽  
Hugo Águas ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Low Cost ◽  
Substrate Surface ◽  
Hexagonal Wurtzite Structure ◽  
Oxide Thin Films ◽  
Large Area ◽  
Axis Orientation

AbstractAluminium doped zinc oxide thin films (ZnO:Al) have been deposited on polyester (Mylar type D, 100 μm thickness) substrates at room temperature by r.f. magnetron sputtering. The structural, morphological, optical and electrical properties of the deposited films have been studied. The samples are polycrystalline with a hexagonal wurtzite structure and a strong crystallographic c-axis orientation (002) perpendicular to the substrate surface. The ZnO:Al thin films with 85% transmittance in the visible and infra-red region and a resistivity as low as 3.6×10−2 ωcm have been obtained, as deposited. The obtained results are comparable to those ones obtained on glass substrates, opening a new field of low cost, light weight, small volume, flexible and unbreakable large area optoelectronic devices.

Charge Transport in Pentacene Thin Film Transistors

2001 ◽  
Vol 665 ◽  
Author(s):  
J. H. Schön ◽  
L. D. Buchholz ◽  
Ch. Kloc ◽  
B. Batlogg
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Single Crystal ◽  
Charge Transport ◽  
Grain Boundaries ◽  
Thin Film Transistors ◽  
Room Temperature ◽  
Nanocrystalline Material ◽  
Hole Mobility ◽  
Grain Sizes

ABSTRACTThe charge transport properties in polycrystalline pentacene thin film transistors is investigated. A potential barrier is formed at grain boundaries due charged trapping states. The influence of such grain boundaries on the hole mobility of the devices is analyzed for different grain sizes, trap concentrations, and carrier densities. The results reveal that room temperature mobilities exceeding 0.5 cm2/Vs can be obtained in thin films with large grains as well as in nanocrystalline material. Consequently, single crystal device limits can be reached also by polycrystalline pentacene thin film transistors.

Defect structure of laser deposited Y-Ba-Cu-O thin films on single crystal MgO substrate

1990 ◽  
Vol 5 (4) ◽  
pp. 704-716 ◽  
Author(s):  
R. Ramesh ◽  
D. M. Hwang ◽  
J. B. Barner ◽  
L. Nazar ◽  
T. S. Ravi ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Defect Structure ◽  
Repeat Sequence ◽  
Structural Defects ◽  
Nominal Composition ◽  
Stacking Sequence ◽  
Antiphase Boundaries ◽  
Edge Dislocations ◽  
Mgo Substrate

Structural defects in thin films of nominal composition YBa2Cu3O7 (123) grown on single crystal MgO have been characterized. The main types of stacking defects correspond to the cationic stoichiometries of “248”, “247”, and “224”. Several types of edge dislocations have been observed. Due to the frequent changes in the stacking sequence, antiphase boundaries are created to accommodate the misfit across regions in which the repeat sequence is not identical. The films exhibit a mosaic microstructure due to the formation of grain boundaries in the a-b plane.

Sign in / Sign up

Export Citation Format

Share Document