Characterization of free-standing GaN substrates prepared by self lift-off

Abstract

Free-standing GaN layers were successfully prepared by self lift-off process. Single crystalline ZnO buffer layer and GaN layer were successively grown on sapphire substrate by plasma assisted molecular beam epitaxy. Thick GaN film was grown on this template substrate for the realization of stress-free free-standing substrate by hydride vapor phase epitaxy. The a-axis and c-axis lattice constants of free-standing GaN were 3.189Å and 5.185Å, respectively. Peak positions of photoluminescence spectrum were D°X of 3.4715 eV and FXA of 3.4791 eV. These results suggest that the stress-free GaN layers were successfully prepared by self lift-off process. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.