Temperature dependence of barrier height in Ni/n-GaN Schottky barrier diode

The temperature dependence of barrier height in a Ni/n-GaN Schottky barrier diode fabricated on a GaN homoepitaxial layer was investigated by capacitance–voltage, current–voltage, and internal photoemission measurements in the range of 223–573 K. The barrier height obtained by these methods linearly decreased with increasing temperature. The temperature coefficient was −(1.7–2.3) × 10 −4 eV/K, which is about half of the temperature coefficient of the band gap reported previously. This indicates that the decrease in the barrier height may mainly reflect the shrinkage of the band gap (lowering of the conduction band edge) in GaN with increasing temperature.