Self-Organized Composition Modulation In Omvpe Ga 1−x In x As y Sb 1−y /GaSb Epitaxial Heterostructures

Microstructures of lattice-matched Gal−xInxAsySbil−y grown by organometallic vapor phase epitaxy (OMVPE) on (100) 6°→ (111)bGaSb substrates have been examined in detail by transmission electron microscopy. A three-dimensional self-organized composition modulation (SOCM) microstructure was found with an orientation inclined 10 degrees to the surface orientation when viewed in (011) cross-section. The periodicity of the SOCM increased from ~13 nm to 20 nm, as x increased from 0.1 to 0.2 while the orientation of the SOCM remained the same. The fact that the orientation was not sensitive to the component composition indicated that substrate misorientation plays a major role in deciding this SOCM orientation. This may open fabrication opportunities for three-dimensional natural superlattices by engineering on the substrate misorientation.