Effect of a Graphene Interlayer on the Electrical Properties of an AlGaN/GaN Schottky Diode

We report a simple method for fabricating AlGaN/GaN Schottky barrier diodes (SBDs) that include a graphene layer inserted between the AlGaN and Ni/Au metal layers. The insertion of a graphene interlayer between the Ni/Au metal pads and AlGaN layer produces a contact with ohmic characteristics. Ohmic and Schottky contacts were achieved by depositing graphene/Ni/Au and Ni/Au, respectively, on the AlGaN surface of SBD. The ohmic contacts formed using graphene/Ni/Au displayed a specific contact resistance of 0.23 Omega. cm(2). The optimum annealing temperature for improving device performance was found to be 500 degrees C. The graphene/metal electrode system suggested herein is promising for improving the electrical characteristics of AlGaN/GaN-based optoelectronic devices.