Microsc Res Tech. 2014 Dec;77(12):980-5. doi: 10.1002/jemt.22424. Epub 2014 Aug 14.

Precession electron diffraction-assisted crystal phase mapping of metastable c-GaN films grown on (001) GaAs.

Microscopy research and technique

Francisco Ruiz-Zepeda, Yenny L Casallas-Moreno, Jesus Cantu-Valle, Diego Alducin, Ulises Santiago, Miguel José-Yacaman, Máximo López-López, Arturo Ponce

PMID: 25123258 DOI: 10.1002/jemt.22424

Abstract

The control growth of the cubic meta-stable nitride phase is a challenge because of the crystalline nature of the nitrides to grow in the hexagonal phase, and accurately identifying the phases and crystal orientations in local areas of the nitride semiconductor films is important for device applications. In this study, we obtained phase and orientation maps of a metastable cubic GaN thin film using precession electron diffraction (PED) under scanning mode with a point-to-point 1 nm probe size beam. The phase maps revealed a cubic GaN thin film with hexagonal GaN inclusions of columnar shape. The orientation maps showed that the inclusions have nucleation sites at the cubic GaN {111} facets. Different growth orientations of the inclusions were observed due to the possibility of the hexagonal {0001} plane to grow on any different {111} cubic facet. However, the generation of the hexagonal GaN inclusions is not always due to a 60° rotation of a {111} plane. These findings show the advantage of using PED along with phase and orientation mapping, and the analysis can be extended to differently composed semiconductor thin films.

© 2014 Wiley Periodicals, Inc.

Keywords: TEM; cubic GaN; phase mapping; precession electron diffraction; thin film

Publication Types

• Journal Article
• Research Support, N.I.H., Extramural
• Research Support, Non-U.S. Gov't
• Research Support, U.S. Gov't, Non-P.H.S.

Grant support

• G12MD007591/MD/NIMHD NIH HHS/United States