The barrier height and interface states of Au/n-GaN Schottky diodes exhibit a triple Gaussian distribution

The current transport characteristics across Au/n-GaN Schottky diodes were investigated using a current–voltage technique over the temperature range 100–300 K. The Schottky barrier height (SBH) extracted from the forward current density–voltage data increased with temperature, whereas the ideality factor decreased. This behavior was explained by invoking three sets of SBH Gaussian distributions over the temperature ranges 100–140 K, 160–200 K, and 220–300 K respectively. Plots of the SBHs versus 1/2kT yielded mean SBHs of 0.50, 0.82 and 1.30 eV, and standard deviations of 0.069, 0.113 and 0.175 V, for the three temperature ranges. Richardson plots that considered barrier inhomogeneity yielded effective Richardson constants of 33.5, 26.7, and 31.4 A cm⁻² K⁻² at 100–140 K, 160–200 K and 220–300 K respectively. The characteristic tunneling energy (E₀₀) was higher than expected when only the carrier concentration of the GaN layer was considered, suggesting that tunneling significantly influenced current transport.