Study on properties of Ga/F-co-doped ZnO thin films prepared using atomic layer deposition

Zinc oxide (ZnO) thin films with co-doped Ga and F were deposited using atomic layer deposition. Structural, electrical, and optical properties of the ZnO thin films were analyzed for different F doping amounts under the condition that the Ga doping amount remained fixed. From the X-ray diffraction analysis results, it was confirmed that the preferred orientation changed from (002) to (100) with changing F amounts. The electrical properties, i.e., carrier concentration and mobility of these co-doped ZnO thin films improved with the F doping amount, resulting in a decrease in the electrical resistivity. The reason for this improved resistivity is that Ga and F atoms replace Zn and O in the lattice sites, respectively, despite a slight decrease in the mobility. An increase in the carrier concentration widened the optical bandgap of ZnO thin films by the Moss-Burstein effect.