Current transport and barrier height evaluation in Ni/InAlN/GaN Schottky diodes

The current-voltage characteristics of the Ni/InAlN/GaN Schottky diodes were measured at various temperatures in the range of 300-700 K. The experimental data were analyzed considering different current-transport mechanisms. From the analysis it follows that the tunneling current, which might be due to a multistep tunneling along dislocations, is the dominant component at all temperatures in the samples investigated. The barrier height of the Ni/InAlN/GaN Schottky diodes, evaluated from the thermionic emission current, shows a slightly negative temperature coefficient and its value at 300 K is >= 1.46 eV. This is significantly higher barrier height than reported before (<1 eV). This discrepancy follows from an incorrect evaluation using the intercept and slope of a measured characteristic without separation of the individual current components. (C) 2010 American Institute of Physics. [doi:10.1063/1.3442486]