Zn0.9Mg0.1O/ZnO p-n junctions grown by pulsed-laser deposition

The electrical characteristics of Zn0.9Mg0.1O/ZnO p-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 3.6-4 V for Pt/Au metallization used for the p-Ohmic contact on Zn0.9Mg0.1O.The reverse breakdown voltage is as high as 9 V, but displays a small negative temperature coefficient of -0.1-0.2 V K-1 over the range 30-200degreesC. 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 Zn(0.9)mg(0.1)O.Without this buffer, the junctions showed very high leakage current. (C) 2004 American Institute of Physics.