Fabrication of a Schottky diode with transfer-free deposition of multilayer graphene on n-GaN by solid-phase reaction

Transfer-free deposition of multilayer graphene (MLG) on n-GaN by a solid-phase reaction was demonstrated for the first time for the fabrication of a Schottky diode. To improve the crystallinity and uniformity of MLG films, a new approach of heat sputtering for the deposition of amorphous carbon (C) and cobalt (Co) as catalyst layers has been investigated. The characteristics obtained by Raman spectroscopy and scanning electron microscopy (SEM) measurements revealed that the crystallinity and uniformity of MLG films were improved significantly by employing heat sputtering rather than conventional room-temperature sputtering. MLG-GaN Schottky diodes were fabricated with optimized deposition of MLG on n-GaN. The Schottky barrier height determined on the basis of the thermionic emission theory using current-voltage (I-V) data was 0.75 eV. The reverse leakage current was found to be of the order of 10%7A/mm2. The obtained results indicate the MLG fabrication on n-GaN by our proposed method might have potential applications in the fabrication of Schottky diodes.