材料期刊网

Various crystal defects in epitaxial GaN film were studied by high-order bright-field and dark-field electron microscopy. The results revealed that the film is composed of small grains in nano-meter scale. Distinct shapes of the grain boundaries and a great number of threading dislocations were shown in the experimental g/3g weak-beam images. Diffraction contrast analysis verified that the majority of threading dislocations is 1/3<11 (2) over bar 0> edge dislocation. A unique (11 (2) over bar 0) planar defect was observed in the specimen. The defect was identified to have a similar structure to the incipient 1/3[11 (2) over bar 0] edge dislocation. (C) Elsevier Science Inc., 2000. All rights reserved.