Multilayer graphene (MLG)/n-GaN Schottky diodes were fabricated by transfer-free deposition of MLG on n-GaN by solid-phase reactions with cobalt as a catalyst. The thermal stability of the diodes was determined from the current-voltage (I-V) characteristics after annealing the diodes in vacuum at 200-500 °C, at intervals of 100 °C. The diode characteristics evaluated using a thermionic emission model and Cheung's function using I-V data revealed that the Schottky barrier diode (SBD) fabricated with MLG as a Schottky contact on n-GaN showed better thermal stability than the conventional Ni/n-GaN SBD. The prevention of Au diffusion to n-GaN with MLG as a diffusion barrier layer and the unaffected interface reactions between n-GaN and MLG are possible reasons for the improved thermal stability, enabling potential application of this new diode in highpower and high-temperature operations.
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