Linear defects and electrical properties of ZnO nanorods

Proton irradiation (17-34 MeV at flux values ranging from 10¹¹ to 10¹² cm^-2) was used to assess the influences of orientation-dependent linear defects in a current passing through ZnO nanorods. Compared with the pristine ZnO nanorods, there was a significant increase in the current passing through ZnO nanorods that were irradiated with a proton beam kept in parallel with the nanorod length. The current was gradually decreased with a corresponding increase in the angle of the proton beams relative to the nanorod length. Calculations using the density functional theory demonstrated a substantial reduction and a lack of influence on the bandgap due to linear defects along the respective c- and the a-axes of the ZnO nanorods. Linear defects likely play roles as channels or traps of conduction electrons or holes in wide-bandgap materials.