Thermal droop in InGaN-based LEDs: physical origin and dependence on material properties

2016 ◽  
Author(s):  
C. De Santi ◽  
M. Meneghini ◽  
M. La Grassa ◽  
N. Trivellin ◽  
B. Galler ◽  
...  
2020 ◽  
Vol 127 (21) ◽  
pp. 211102 ◽  
Author(s):  
Matteo Meneghini ◽  
Carlo De Santi ◽  
Alberto Tibaldi ◽  
Marco Vallone ◽  
Francesco Bertazzi ◽  
...  

1997 ◽  
Vol 161 ◽  
pp. 505-510
Author(s):  
Alexandra J. MacDermott ◽  
Laurence D. Barron ◽  
Andrè Brack ◽  
Thomas Buhse ◽  
John R. Cronin ◽  
...  

AbstractThe most characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. We therefore suggest that a search for extra-terrestrial life can be approached as a Search for Extra- Terrestrial Homochirality (SETH). The natural choice for a SETH instrument is optical rotation, and we describe a novel miniaturized space polarimeter, called the SETH Cigar, which could be used to detect optical rotation as the homochiral signature of life on other planets. Moving parts are avoided by replacing the normal rotating polarizer by multiple fixed polarizers at different angles as in the eye of the bee. We believe that homochirality may be found in the subsurface layers on Mars as a relic of extinct life, and on other solar system bodies as a sign of advanced pre-biotic chemistry. We discuss the chiral GC-MS planned for the Roland lander of the Rosetta mission to a comet and conclude with theories of the physical origin of homochirality.


Author(s):  
C.L. Briant

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.


Author(s):  
Brian Ralph ◽  
Barlow Claire ◽  
Nicola Ecob

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.


2016 ◽  
Author(s):  
Frank Malgo ◽  
Neveen A T Hamdy ◽  
Alberto M Pereira ◽  
Nienke R Biermasz ◽  
Natasha M Appelman-Dijkstra

2015 ◽  
Vol 10 (2) ◽  
pp. 57-68 ◽  
Author(s):  
Klára Machalická ◽  
Martina Eliášová ◽  
Michal Netušil

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