Defect studies in strained-layer quantum well heterostructures

Author(s):  
J.M. Brown ◽  
M.E. Mochel ◽  
N. Holonyak ◽  
M.D. Camras ◽  
M.J. Ludowise ◽  
...  

The epitaxial growth of mismatched or strained III-V layers was shown to be viable as early as 1960. Osbourn et al suggested that strained layer GaP-GaAs1-xPx superlattices grown by organo-metal1ic vapor phase epitaxy (OMVPE) could be used to fold the Brillouin zone and make indirect-crystal direct. More recently, it has been shown that a strained-layer superlattice can be grown free enough of defects at heterointerfaces to make possible stimulated emission. This has been demonstrated on OMVPE GaAs1-xPx-GaAs (x=0.25) and GaAs-InxGa1-xAs (x=0.2) strained layer superlattices which have been operatedas photopuraped continuous (cw) 300K lasers but which at high excitation levels (> 103Acm-2) prove to be unstable. This paper presents the results of an electron microscope study of the defects produced in a GaAs-InxGa1-xAs strained superlattice as a result of high excitation levels of operation.

Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).


Author(s):  
A. Campos ◽  
J. Vilches ◽  
J. Gomez

Microgranules have been described with different names in keratinized and in nonkeratinized epithelium. In keratinized epithelium it seems clear that the microgranules are lamellated bodies bounded by a membrane which empty their contents into the intercellular space. Their existence in nonkeratinized epithelium is more debatable. Until now the so-called microgranules have been described in nonkeratinized bucal, lingual and cervical epithelium. In the present work we describe the morphology and nature of such structures in human vaginal epithelium.Biopsies from the midlevel of the vaginal mucosa were taken from voluntary fertile women. The specimens were divided into three groups with four vaginal specimens. The first group was obtained in the folicular phase; those of the second in the postovulatory phase and, finally, the last group corresponded to the secretory phase.


1979 ◽  
Vol 41 (04) ◽  
pp. 655-661 ◽  
Author(s):  
L Tranqui ◽  
M H Prandini ◽  
M Suscillon

1980 ◽  
Vol 42 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Shuhei IMAYAMA ◽  
Hiromu KOHDA ◽  
Harukuni URABE

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