Low defect-mediated reverse-bias leakage in (0001) GaN via high-temperature molecular beam epitaxy

Conductive atomic force microscopy, scanning electron microscopy, and x-ray diffraction were used to determine the effects of Ga/N flux ratio on the conductivity of current leakage paths in GaN grown by molecular beam epitaxy. Our data reveal a band of fluxes near Ga/N≈1 for which these pathways ceased to be observable. We conclude that changes in surface defects surrounding or impurities along screw-component threading dislocations are responsible for their conductive nature. These observations suggest a method for controlling the primary source of reverse-bias Schottky contact leakage in n-type GaN grown by molecular beam epitaxy.