Formation mechanisms and structure of the luminescence spectra of a dense resonant medium

1998 ◽  
Vol 87 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Yu. K. Zemtsov ◽  
A. Yu. Sechin ◽  
A. N. Starostin ◽  
A. G. Leonov ◽  
A. A. Rudenko ◽  
...  
Author(s):  
B. Cunningham ◽  
D.G. Ast

There have Been a number of studies of low-angle, θ < 4°, [10] tilt boundaries in the diamond lattice. Dislocations with Burgers vectors a/2<110>, a/2<112>, a<111> and a<001> have been reported in melt-grown bicrystals of germanium, and dislocations with Burgers vectors a<001> and a/2<112> have been reported in hot-pressed bicrystals of silicon. Most of the dislocations were found to be dissociated, the dissociation widths being dependent on the tilt angle. Possible dissociation schemes and formation mechanisms for the a<001> and a<111> dislocations from the interaction of lattice dislocations have recently been given.The present study reports on the dislocation structure of a 10° [10] tilt boundary in chemically vapor deposited silicon. The dislocations in the boundary were spaced about 1-3nm apart, making them difficult to resolve by conventional diffraction contrast techniques. The dislocation structure was therefore studied by the lattice-fringe imaging technique.


Author(s):  
Eal H. Lee ◽  
Helmut Poppa

The formation of thin films of gold on mica has been studied in ultra-high vacuum (5xl0-10 torr) . The mica substrates were heat-treated for 24 hours at 375°C, cleaved, and annealed for 15 minutes at the deposition temperature of 300°C prior to deposition. An impingement flux of 3x1013 atoms cm-2 sec-1 was used. These conditions were found to give high number densities of multiple twin particles and are based on a systematic series of nucleation experiments described elsewhere. Individual deposits of varying deposition time were made and examined by bright and dark field TEM after "cleavage preparation" of highly transparent specimens. In the early stages of growth, the films generally consist of small particles which are either single crystals or multiply twinned; a strong preference for multiply twinned particles was found whenever the particle number densities were high. Fig. 1 shows the stable cluster density ns and the variation with deposition time of multiple twin particle and single crystal particle densities, respectively. Corresponding micrographs and diffraction patterns are shown in Fig. 2.


1996 ◽  
Vol 442 ◽  
Author(s):  
V. Valdna

AbstractPhotoluminescence and conductivity of doped with chlorine and copper ZnTe, Zn(SeTe) and CdTe are investigated. We suppose that interstitial tellurium and complex defects of Tei with a donor dopant Cl can significantly affect the luminescence spectra and conductivity value of ZnTe and CdTe. This assumption is confirmed experimentally. We found that copper dopant in CdTe: Cl can increase the resistivity value of p-type CdTe.


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