Co-doping Deposition of p-type ZnO Thin Films using KrF Excimer Laser Ablation

Abstract

ABSTRACTWe report on the attempt to fabricate p-type ZnO thin films using various doping techniques based on the pulsed laser deposition (PLD). As an accepter, we have doped the N atom by using high purity nitric monoxide (NO) ambient gas. NO is dissociated into N and O at an energy of 6.5 eV which is lower than at N2 (9.76 eV). Moreover the dissociation reaction of NO is simpler than other nitrogenous gases such as N2O, NO2, and NH3. One of our doping techniques is co-doping of Ga and N atom by ablating ZnO:Ga target in NO gas, and another is the ablation of the metal Zn target in NO gas. Both of Ga and N co-doped ZnO films and N doped ZnO films have c-axis orientation as well as undoped ZnO films. The surfaces of these doped films are rough while the undoped ZnO thin film is very smooth and have hexagonally shaped grains. We found it possible to fabricate the p-type ZnO film by ablating the metal Zn target in NO gas.