scholarly journals Сильная связь экситонов в микрорезонаторах GaN гексагональной формы

Author(s):  
А.В. Белоновский ◽  
Г. Позина ◽  
Я.В. Левитский ◽  
К.М. Морозов ◽  
М.И. Митрофанов ◽  
...  

The GaN planar hexagonal microcavities were grown by a selective vapor phase epitaxy. The spectra were measured by the low-temperature cathodoluminescence method in-situ scanning electron microscope. The obtained spectra show a huge Rabi splitting (in order of 100 meV). Numerical simulation of the spatial distribution of the modes’ intensities of a hexagonal resonator is shown. Some modes can have strong spatial localization, leading to strong coupling with the exciton and huge Rabi splitting. Theoretically, we calculated the fraction of excitons in polariton modes, which correlates with the intensity of exciton radiation associated with these modes, for microcavities of a hexagonal shape. Thus, we have obtained the form of the dependence of the radiation probability on the eigenfrequencies of the structure.

Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Eugene L. Vigil

Investigators have long realized the potential advantages of using a low temperature (LT) stage to examine fresh, frozen specimens in a scanning electron microscope (SEM). However, long working distances (W.D.), thick sputter coatings and surface contamination have prevented LTSEM from achieving results comparable to those from TEM freeze etch. To improve results, we recently modified techniques that involve a Hitachi S570 SEM, an Emscope SP2000 Sputter Cryo System and a Denton freeze etch unit. Because investigators have frequently utilized the fractured E face of the plasmalemma of yeast, this tissue was selected as a standard for comparison in the present study.In place of a standard specimen holder, a modified rivet was used to achieve a shorter W.D. (1 to -2 mm) and to gain access to the upper detector. However, the additional height afforded by the rivet, precluded use of the standard shroud on the Emscope specimen transfer device. Consequently, the sample became heavily contaminated (Fig. 1). A removable shroud was devised and used to reduce contamination (Fig. 2), but the specimen lacked clean fractured edges. This result suggested that low vacuum sputter coating was also limiting resolution.


Author(s):  
F. H. Louchet ◽  
L. P. Kubin

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.


2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.


Holzforschung ◽  
1996 ◽  
Vol 50 (6) ◽  
pp. 487-490 ◽  
Author(s):  
Josef Bodner ◽  
Gerhard Grüll ◽  
Michael Georg Schlag

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