Contacts to p-type ZnMgO

Ohmic and Schottky contacts to p-type Zn0.9Mg0.1O are reported. The lowest specific contact resistivity of 3×10−3 Ω cm2 was obtained for Ti/Au annealed at 600 °C for 30 s. Ni/Au was less thermally stable and showed severe degradation of contact morphology at this annealing temperature. Both Pt and Ti with Au overlayers showed rectifying characteristics on p-ZnMgO, with barrier heights of ∼0.55–0.56 eV and ideality factors of ∼1.9. Comparison of these results with the same metals on n-type ZnO indicates that high surface state densities play a significant role in determining the effective barrier height.