Size-dependent Schottky barrier height in self-assembled gold nanoparticles

(Au nanocluster)/6H-SiC Schottky contacts were electrically characterized by conductive atomic force microscopy, collecting a high number of current-voltage (I-V) curves. The main observed result is the Schottky barrier height (SBH) dependence on the cluster size. The SBH increases from 1.35 +/- 0.01 to 1.77 +/- 0.01 eV when the cluster size increases from 1.5 to 6.8 nm and it tends, asymptotically, to the theoretical SBH of the macroscopic contact Au/SiC (similar to 1.9 eV). This behavior is interpreted considering the thermoionic transport theory through the Au cluster/SiC barrier coupled with the concept of ballistic transport within few electron quantum dots.