Effect of the starting surfaces of GaN on defect formation in epitaxial Co thin films

Growths of Co epifilms on GaN(0001)-"1 x 1" and (1 x 1) surfaces were studied, where the structural properties of the crystals and the interfaces are compared. Stacking faults are seen to be abundant in epitaxial Co films grown on excess Ga covered GaN(0001)-"1 x 1" surface. Such stacking defects are effectively suppressed in Co films grown on less excess Ga covered GaN(0001)-(1 x 1) surfaces. The hetero-interface between Co and GaN(0001) is characterized by a disordered or amorphous region, and diffusion of Ga and N from the substrate into Co is suggested. (C) 2011 American Institute of Physics. [doi:10.1063/1.3652761]