Structural and chemical characterization of free-standing GaN films separated from sapphire substrates by laser lift-off

2000 ◽  
Vol 77 (12) ◽  
pp. 1819 ◽  
Author(s):  
E. A. Stach ◽  
M. Kelsch ◽  
E. C. Nelson ◽  
W. S. Wong ◽  
T. Sands ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Free Standing ◽  
Sapphire Substrates ◽  
Lift Off

Free Standing CVD Diamond Shapes and Coatings

1989 ◽  
Vol 162 ◽  
Author(s):  
Donald E. Patterson ◽  
Robert H. Hauge ◽  
John L. Margrave
Keyword(s):  
Film Industry ◽  
Chemical Characterization ◽  
Cvd Diamond ◽  
Thin Wall ◽  
Low Friction ◽  
Free Standing ◽  
Practical Applications ◽  
Support Materials ◽  
Physical And Chemical

ABSTRACTThe success of the emerging CVD diamond film industry will depend to a great extent on how well these films can be put to practical applications. Our research is presently focusing on the development of methods for the growth of large thin wall diamond shapes which can be subsequently strongly bonded to other support materials. The shapes such as cylinders, hemispheres, etc. will be designed to take advantage of diamond's superior hardness and thermal conductivity. As these diamond shapes also promise low friction and long wearing surfaces, they have potential uses as bearing surfaces as well as very scratch resistant covers for mirrors and lenses. Our primary research objectives will be concerned with: 1. The development of various apparatus to grow selected shapes of CVD diamond. 2. The development of techniques to transfer and bond the films onto materials other than the original substrates. 3. The physical and chemical characterization of the diamond films, composites, and final products.

Characterization of free-standing GaN substrates prepared by self lift-off

2007 ◽  
Vol 4 (7) ◽  
pp. 2617-2620 ◽  
Author(s):  
S. W. Lee ◽  
H. Goto ◽  
T. Minegishi ◽  
W. H. Lee ◽  
J. S. Ha ◽  
...  
Keyword(s):  
Free Standing ◽  
Lift Off

Structural Characterization Of Laser Lift-Off GaN

2000 ◽  
Vol 617 ◽  
Author(s):  
Eric A. Stach ◽  
M. Kelsch ◽  
W.S. Wong ◽  
E.C. Nelson ◽  
T. Sands ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Characterization ◽  
High Resolution Electron Microscopy ◽  
Economic Benefits ◽  
Thin Layers ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Lift Off ◽  
Microscopy Techniques

AbstractLaser lift-off and bonding has been demonstrated as a viable route for the integration of III-nitride opto-electronics with mainstream device technology. A critical remaining question is the structural and chemical quality of the layers following lift-off. In this paper, we present detailed structural and chemical characterization of both the epitaxial layer and the substrate using standard transmission electron microscopy techniques. Conventional diffraction contrast and high resolution electron microscopy indicate that the structural alteration of the material is limited to approximately the first 50 nm. Energy dispersive electron spectroscopy line profiles show that intermixing is also confined to similar thicknesses. These results indicate that laser lift-off of even thin layers is likely to result in materials suitable for device integration. Additionally, because the damage to the sapphire substrate is minimal, it should be possible to polish and re-use these substrates for subsequent heteroepitaxial growths, resulting in significant economic benefits.

Free standing GaN nano membrane by laser lift-off method

2012 ◽  
Vol 1432 ◽  
Author(s):  
Liang Tang ◽  
Yuefeng Wang ◽  
Gary Cheng ◽  
Michael J. Manfra ◽  
Timothy D. Sands
Keyword(s):  
Defect Density ◽  
Sacrificial Layer ◽  
Pulsed Laser ◽  
Large Area ◽  
Free Standing ◽  
Sapphire Substrates ◽  
Device Applications ◽  
Lift Off ◽  
Gan Film

ABSTRACTIn this work, we present a method able to fabricate thin GaN nanomembranes fit for device applications. Starting from commercial GaN on sapphire substrates, MBE was used to deposit a sacrificial layer, which comprises of a superlattice of InN/InGaN, after which thin a GaN film of hundreds of nanometers thickness was grown on top. Pulsed laser irridiation with photon energy of 2.3eV gives rise to the controlled decomposition of the sacrificial intermediate layer, which can be followed by easy separation of the top GaN membrane from the substrate. This process can be used to manufacture GaN membranes with low defect density and a wider range of thickness. We demonstrated that large area, free-standing GaN membranes, with a thickness from 200nm and up, could be made using this method, and the high crystal quality of the lift-off GaN layers is well preserved in this process.

Olfactory and Chemical Characterization of Indoor Air-Towards a Psychophysical Model for Air Quality

1981 ◽  
Author(s):  
Birgitta Berglund ◽  
Ulf Berglund ◽  
Thomas Lindvall ◽  
Helene Nicander-Bredberg
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Chemical Characterization

PURIFICATION AND PARTIAL CHEMICAL CHARACTERIZATION OF SHEEP NEUROPHYSIN

1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Chemical Characterization ◽  
Terminal Amino Acid ◽  
Amino Acid Determination ◽  
Pituitary Glands ◽  
Terminal Amino ◽  
Partial Chemical ◽  
Acid Determination

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.

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