Dependence of reverse bias leakage on depletion width and V-pit size in InGaN/GaN light-emitting diodes grown on silicon

The reverse bias leakage characteristics of InGaN/GaN light emitting diodes (LEDs) grown on Si (111) were investigated as a function of two factors: (1) bulk depletion width and (2) V-pit size. The reverse leakage current showed a decreasing trend with an increase in V-pit size, given a fixed depletion width. Atomic probe tomography was used to verify that a reduction in electric field near the vicinity of threading dislocations suppresses field-assisted carrier emission, reducing reverse leakage. Calculations using the appropriate theory show a reasonable agreement with the experimental results. These findings further elucidate the role of V-pits as passivation for reverse leakage paths and may be useful for not only LEDs but GaN-based power devices as well. (C) 2015 American Vacuum Society.