Conductivity of single ZnO nanorods after Ga implantation in a focused-ion-beam system

ZnO nanorods were implanted with Ga+ ions in a combined scanning-electron-microscope/focused-ion-beam system with doses from 10(11) to 10(17) cm(-2). Electrical resistance measurements performed on single ZnO nanorods yield first an increase of the resistance due to defect formation which lowers the electron mobility. Implantation doses exceeding 10(15) cm(-2) yield a strong decrease of the resistance to values significantly below the resistance before Ga+-ion implantation. Low specific resistivities of about 3x10(-3) Omega cm are reached without additional annealing treatment after high-dose implantation. (c) 2007 American Institute of Physics.