Elimination of Stacking Faults in Semipolar GaN and Light-Emitting Diodes Grown on Sapphire.

Abstract

We report a novel approach to eliminate stacking faults (SFs) and prepare large-area, SF-free semipolar gallium nitride (GaN) on sapphire substrates. A root cause of the formation of basal-plane SFs is the emergence of N-polar (0001̅) facets during semipolar and nonpolar heteroepitaxies. Invoking the concept of kinetic Wulff plot, we succeeded in suppressing the occurrence of N-polar GaN (0001̅) facets and, consequently, in eliminating the stacking faults generated in (0001̅) basal planes. Furthermore, InGaN light-emitting diodes with promising characteristics have been produced on the SF-free semipolar (202̅1) GaN on sapphire substrates. Our work opens up a new insight into the heteroepitaxial growth of nonpolar/semipolar GaN and provides an approach of producing SF-free nonpolar/semipolar GaN material over large-area wafers, which will create new opportunities in GaN optoelectronic and microelectronic research.