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Polarity determination of rough and smooth surface grains in AlN crystals
Author(s) -
Nyakiti L. O.,
Lee R. G.,
Gu Z.,
Edgar J. H.,
Chaudhuri J.
Publication year - 2012
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201200005
Subject(s) - polarity (international relations) , transmission electron microscopy , materials science , grain boundary , electron diffraction , diffraction , crystallography , nitride , polar , oxide , solubility , crystal (programming language) , microstructure , chemistry , optics , composite material , nanotechnology , metallurgy , physics , biochemistry , layer (electronics) , astronomy , computer science , cell , programming language
The polarity of rough and smooth grains in textured aluminum nitride boules were analyzed by transmission electron microscopy. Specifically, convergent beam electron diffraction method was applied to determine polarity. The grains corresponding to smooth and rough surfaces were identified as having Al and N polarities, respectively. Aluminum oxide (Al 2 O 3 ) was observed to form at the grain boundaries. The oxide may precipitate due to the low mutual solubility between Al 2 O 3 and AlN at the high crystal growth temperature (∼2000°C). Oxygen may be the cause of polarity inversion that leads to the formation of Al and N polar grains.