Pyrolytic and Laser Photolytic Growth of Crystalline and Amorphous Germanium Films from Digermane (Ge2H6)

1988 ◽  
Vol 131 ◽  
Author(s):  
Djula Eres ◽  
D. H. Lowndes ◽  
J. Z. Tischler ◽  
J. W. Sharp ◽  
D. B. Geohegan ◽  
...  

ABSTRACTHigh-purity digermane (Ge2H6, 5% in He) has been used to grow epitaxially oriented crystalline Ge films by pyrolysis. Amorphous Ge:H films also have been deposited by pyrolysis and ArF (193 nm) laser-induced photolysis. The amorphous-to-crystalline transition and the film's morphology was studied as a function of deposition conditions. The film's microstructure, strain and epitaxial quality were assessed using x-ray diffraction curves and scanning and transmission electron microscopy. It was found that commensurate, coherently strained epitaxial Ge films could be grown pyrolytically on (100) GaAs at low (0.05–40 m Torr) Ge2H6 partial pressures, for substrate temperatures above 380°C.

1992 ◽  
Vol 275 ◽  
Author(s):  
S. K. Streiffer ◽  
B. M. Lairson ◽  
E. M. Zielinski ◽  
J. C. Bravman

ABSTRACTQuantitative high resolution transmission electron microscopy and x-ray diffraction have been used to study films of YBa2Cu3O7-δ grown on LaAlO3 substrates at low substrate temperatures. Based on analysis of high-resolution micrographs, it is asserted that the films are b-axis oriented near the film-substrate interface, and switch to a-axis oriented at some distance away from the interface, in a manner which varies from sample to sample. Thus, the films undergo a change in orientation as a function of distance from the substrate. X-ray diffraction confirms that these films contain both a-axis oriented and b-axis oriented components normal to the plane of the substrate, consistent with the high-resolution microscopy data.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Guodong Zhang ◽  
Nian Liu ◽  
Zhengyuan Ren ◽  
Bing Yang

This paper presents a new method to synthesize high-purity single-crystalline SnO2nanobelts with rutile structure. The purity, morphology, crystal structure, and sizes of the as-grown SnO2nanobelts are characterized by X-ray diffraction, energy-dispersive X-ray analysis, scanning electron microscopy, transmission electron microscopy, and Raman-scattering spectroscopy. The scanning electron microscopy and transmission electron microscopy reveal tetragonal SnO2nanobelts of 50–120 nm in width, 20–50 nm in thickness, and 2–10 μm in length. The three observed Raman peaks at 475, 633, and 774 cm−1indicate the typical rutile structure of the SnO2, which is in agreement with the X-ray diffraction results, and other peaks of impurity are not found. High-resolution transmission electron microscopy demonstrates that the nanobelts have a high degree of crystallinity, without typical imperfects in it. And the growth mechanism of the SnO2nanobelts is discussed.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.


Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...


1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.


2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


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