Microstructure of epitaxial Mg 3 N 2 thin films grown by MBE

Description

The epitaxial growth of Mg 3 N 2 thin films by molecular beam epitaxy has been recently achieved. This work presents the structural properties of the films, including grains sizes and lattice rotations, as assessed by x-ray diffraction and transmission electron microscopy. The films' microstructure consists of well-aligned columnar grains 10 nm in diameter that nucleate at the film/substrate interface and that display a significant column twist, in the order of 2.5°. As growth proceeds, tilted and twisted mosaic blocs overgrow these columns, as observed in to many other epitaxial semiconductors. Yet, the rocking curves on symmetric reflections display extremely narrow peaks (∼50 arcseconds), revealing a long-range spatial correlation between structural defects that should not be mistakenly considered as a proof of high crystalline quality.

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