Zn 0.9 Mg 0.1 O ∕ ZnO p – n junctions grown by pulsed-laser deposition

The electrical characteristics of Zn0.9Mg0.1O∕ZnOp–n junctions grown by pulsed-laser deposition on bulk, single-crystal ZnO substrates are reported. The forward turn-on voltage of the junctions was in the range 3.6–4V for Pt∕Au metallization used for the p-Ohmic contact on Zn0.9Mg0.1O.The reverse breakdown voltage is as high as 9V, but displays a small negative temperature coefficient of −0.1–0.2VK−1 over the range 30–200°C. The achievement of acceptable rectification in the junctions required growth of an n-type ZnO buffer on the ZnO substrate prior to growth of the p-type, phosphorus-doped Zn0.9mg0.1O.Without this buffer, the junctions showed very high leakage current.