Formation of nonalloyed low resistance Ni/Au ohmic contacts to p-type GaN using Au nanodots

The effects of the insertion of Au nanodots (4-10 nm in diameter) at the Ni/GaN interface on the electrical properties of Ni/Au ohmic contacts to p-type GaN have been investigated. As-deposited Ni/Au contacts with Au nanodots show better electrical behavior than contacts without Au nanodots. Nanodot contacts produce a specific contact resistance of 8.4 × 10^-4 Ω cm². The multiquantum-well light-emitting diodes (LEDs) are fabricated with the nanodot Ni/Au contact layers. Nanodot LEDs show a lower operating voltage compared with LEDs made with a conventional Ni/Au contact layer.