Fabrication of homostructural ZnO p–n junctions and ohmic contacts to arsenic-doped p-type ZnO

We report fabrication of homostructural ZnO p–n junctions that contain arsenic (As)-doped ZnO (ZnO:As) and intrinsic n-type ZnO layers. We also describe the metallization process for forming ohmic contacts to p-type ZnO. ZnO films were synthesized on n-type SiC substrates by hybrid beam deposition. Ni/Au metal contacts show linear I–V characteristics indicative of ohmic behavior, while other metal contacts (e.g., In/Au and Ti/Au) show nonlinear characteristics with rectification that reveal the presence of Schottky barriers. The characteristics for p–n junctions composed of ZnO layers are confirmed by I–V measurements.