The effect of dislocations upon the electrical characteristics of p-n junctions was investigated by using current-voltage measurements. Lateral epitaxial overgrowth was used to produce areas of low dislocation density which were close to areas having the high dislocation density that was typical for growth on sapphire. A comparison of p-n diodes which were fabricated in each region revealed that reverse-bias leakage current was reduced by 3 orders of magnitude on lateral epitaxial overgrowth samples. Temperature-dependent measurements of the diodes indicated that the remaining leakage current was associated with a deep trap level.

Electrical characterization of GaN p-n junctions with and without threading dislocations P.Kozodoy, J.P.Ibbetson, H.Marchand, P.T.Fini, S.Keller, J.S.Speck, S.P.DenBaars, U.K.Mishra: Applied Physics Letters, 1998, 73[7], 975-7