I - V characteristics of Au∕Ni Schottky diodes on GaN with SiNx nanonetwork

Room temperature and temperature dependent current-voltage characteristics of Ni∕Au Schottky diodes fabricated on undoped GaN prepared with and without in situ SiNx nanonetwork by metal organic chemical vapor deposition have been studied. The features of the Schottky diodes depend strongly on the SiNx deposition conditions, namely, its thickness. Reduction in the point and line defect densities caused the Schottky barrier height to increase to 1.13eV for 5min SiNx deposition time as compared to 0.78eV without SiNx nanonetwork. Similarly, the breakdown voltage also improved from 76V for the reference to 250V when SiNx nanonetwork was used. With optimized SiNx nanonetwork, full width at half maximum values of (0002) and (101¯2) x-ray rocking curves improved to 217 and 211arcsec, respectively, for a 5.5μm thick layer, as compared to 252 and 405arcsec for a reference sample of the same thickness, which are comparable to literature values. The photoluminescence linewidth also reduced to 2.5meV at 15K with free excitons A and B clearly resolvable.