Transparent RuO[sub x] Contacts on n-ZnO

thick Ru films were deposited onto n-ZnO epitaxial layers by radio frequency sputtering. It was found that highly transparent was formed after annealing. With an incident wavelength of , it was found that transmittances of as-grown, -annealed, -annealed, and -annealed Ru films were 56.8, 73.5, 79.6, and 86.8%, respectively. It was also found that as-deposited Ru formed Schottky contact on n-ZnO. However, good ohmic contacts were formed between the annealed Ru films and the underneath ZnO. With annealing, we achieved a specific contact resistance of only . Such a low specific contact resistance should be attributed to the formation of and the dissociation of oxygen atoms in ZnO during annealing.