Nonalloyed Ohmic contacts on p-AlGaN were achieved using a thin polymer film [i.e., poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(4-styrenesulfonate)] as an interlayer for the electronic modification of indium tin oxide/p-AlGaN contacts. The electronic properties were investigated by current-voltage measurements and x-ray photoelectron spectroscopy (XPS). According to XPS measurements, the authors found a slight reduction in the surface band bending of p-AlGaN following PEDOT coating and the disappearance of the barrier for hole transport at indium tin oxide/PEDOT/p-AlGaN interfaces.
