Analysis of current–voltage measurements on Au/Ni/n-GaN Schottky contacts in a wide temperature range

Current–voltage characteristics of Au/Ni/n-GaN Schottky contacts have been measured in the 60–320 K temperature range. The zero bias barrier height, ϕbo and ideality factor, n have been studied as a function of temperature. The sharp increase in ideality factor at low temperatures has been explained as an effect of thermionic field emission. The deviation of the characteristics from the ideal thermionic behaviour is more pronounced with a decrease in temperature, in which the results obtained indicate the presence of other current transport mechanisms in the 60–280 K temperature range and the dominance of pure thermionic emission current at 300 K. The increase in barrier height with increasing temperature has been explained as an effect of barrier inhomogeneities.