Control of Conduction Type in Al- and N-codoped ZnO Thin Films

p -type ZnO thin films have been fabricated by an Al- and N-codoping technique at the growth temperature between 380 and 480 °C, as identified by the Hall measurement. At lower and higher temperatures, however, the samples are n type. The best p -type sample shows a resistivity and hole concentration of 24.5 Ωcm and 7.48×1017 cm-3 at room temperature, respectively. Spread resistance depth profile further shows the transition from n -type substrate to p -type ZnO through a clearly defined depletion region. Photoluminescence spectra also show low signal in deep level transition, indicating a low density of native defects.