Fabrication of hexagonal GaN on the surface of β-Ga_2O_3 single crystal by nitridation with NH_3

摘要

The fabrication of GaN on the surface of a bulk β-Ga_2O_3 single crystal by nitridation with NH_3 was investigated for the purpose of using it as a isubstrate for GaN epitaxial growth. A β-Ga_2O_3 single crystal was prepared using a floating zone furnace with double ellipsoidal mirrors, and its polished (100) plane was nitridated in NH_3 atmosphere at 850℃ for 5 h. It was found that hexagonal GaN with preferred in-plane orientation was produced on the surface of β-Ga_2O_3, and the thickness of nitride layers was approximately 50 nm. High resolution transmission electron microscopic observation indicated that the synthesized GaN was composed of the aggregation with single crystalline GaN particles, whose size iranged from ～5 nm to ～50 nm, and dislocation or defect was not observed in a GaN particle. This method could be expected as a new route to fabricate a substrate for epitaxial growth of III-nitride materials instead of using a bulk GaN single crystal.