Catalytic role of Au in Ni/Au contact on GaN(0001)

We investigated the structural behavior of the Ni/Au contact on GaN(0001) and found the catalytic role of Au during annealing, using in situ x-ray scattering. The oxidation kinetics of Ni during annealing in air was greatly affected by the presence of Au. The accelerated GaN decomposition and Ni nitride formation during annealing in ${\mathrm{N}}_{\mathrm{2}}$ also provide evidence of the catalytic role of Au. The results suggest that oxidized Ni/Au ohmic contact exhibit better thermal stability than that of the ${\mathrm{N}}_{\mathrm{2}}$ annealed Ni/Au contacts.