Preparation and Characterization of Zn-Se Bilayer Structure

Author(s):  
M. Singh ◽  
J.S. Arora ◽  
Kamlendra Awasthi ◽  
R. Nathawat ◽  
Y.K. Vijay
Keyword(s):  
2007 ◽  
Vol 31 ◽  
pp. 153-157
Author(s):  
M. Singh ◽  
J.S. Arora ◽  
Kamlendra Awasthi ◽  
R. Nathawat ◽  
Y.K. Vijay

The Zn-Se bilayer structure prepared using thermal evaporation method at pressure 10-5 Torr. These films annealed in the vacuum for two hours on different constant temperatures. The optical band gap was found to be varying with annealing temperature due to removal of defects and increase in grain size. It was also observed by the X-ray diffraction pattern the grain size of the film increase with annealing temperature. The lattice constant of hexagonal structure of these films is found to be a =b=4.42Å and c=5.68Å. The dominant peaks to be at 23.2°,28° and 43.9° having values (100), (002) and (111) respectively. The Rutherford back scattering data of these films confirmed the mixing of elements with time.


1989 ◽  
Vol 146 ◽  
Author(s):  
Ahmad Kermani ◽  
John Kuehne

ABSTRACTRapid thermal nitridation (RTN) of metastable Ti silicide in pure ammonia ambient has been shown to result in the formation of a bilayer TiSi 2'TiN structure. This bilayer structure provides an effective self-aligned diffusion barrier against aluminum spiking. Further, the simultaneous formation of TiN on top of the TiSi2 preserves the low resistivity of the silicide layer upon subsequent high temperature process steps. Rutherford backscatttering spectroscopy, Auger electron spectroscopy and four point probe techniques were used to analyze the stoichiometry of the nitrided layer, and to study the kinetics of the nitridation reaction. The nitridation of the metastable silicide film is a substitutional eaction which begins at the surface of the silicide and progresses by substituting nitrogen atoms for silicon. The nitrogen atoms result from dissociation of ammonia The released silicon atoms then diffuse to the silicide'silicon interface and deposit in an epitaxial manner. The benefits of the proposed metallization scheme are substantiated by electrical characterization of the bilayer structure in comparison with a conventional process.


1989 ◽  
Vol 4 (2) ◽  
pp. 440-446 ◽  
Author(s):  
B. Aurian-Blajeni ◽  
M. M. Boucher ◽  
A. G. Kimball ◽  
L. S. Robblee

In the present work we characterize sputtered iridium oxide films (SIROF) by differential scanning calorimetry (DSC), x-ray, and impedance spectroscopies. We show that a crystallization transition occurs at ca, 230 °C, and suggest a bilayer model for the sputtered film. The transition results in a crystalline mixture of iridium metal and iridium oxide; this suggests a decomposition-crystallization process of the type 2Ir2O3 ⇉ Ir + 3IrO2. In the bilayer model proposed by us, the layer closer to the substrate would reflect the combined influence of the sputtering conditions and of the substrate, while the properties of the second layer depend on the sputtering conditions alone. The bilayer structure is supported by results obtained by impedance spectroscopy.


2011 ◽  
Author(s):  
D. M. Phase ◽  
Ridhi Master ◽  
A. D. Wadikar ◽  
R. J. Choudhary ◽  
Alka B. Garg ◽  
...  
Keyword(s):  

Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.


Author(s):  
B. H. Kear ◽  
J. M. Oblak

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


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