Determination of intrinsic barrier height in the Au/n-GaN contact system

We have measured the intrinsic Schottky barrier height of Au/n-GaN metal–semiconductor diodes by performing current–voltage measurement on a series of diodes with varying in the range 1017–1019 cm−3 in the GaN layer. The effective barrier height (ΦB) monotonically decreases with increasing doping level. Taking account of the image-charge lowering (ΔΦ), the intrinsic barrier height ΦB0=ΦB+ΔΦ, is almost constant at (0.934±0.015) V up to ∼5×1018 cm−3, which is close to the Schottky limit of 0.94 V.