Microstructure Characterization of Cu-Alloyed GaN Grown by Plasma Assisted Molecular Beam Epitaxy

Cu-alloyed GaN epilayers were prepared by plasma assisted molecular beam epitaxy with Cu-to-Ga beam equivalent pressure ratio of 1.2 to 4.8 %. Islands enriched with Cu were found on the GaN epitaxial layers grown in a Ga-rich environment. The islands are composed of a Cu9Ga4 intermetallic phase and GaN between which an orientation relationship was identified as [111]Cu9Ga4//[1 10]GaN and (10 )Cu9Ga4//(0001)GaN. X-ray spectroscopy analyses indicated that the 1.2 % and 4.8 % samples contains 0.10 0.02 wt.%Cu and 0.04 0.03 wt.%Cu, respectively.