In this study, Ga-doped ZnO ͑GZO͒ films deposited on a sapphire utilizing magnetron cosputtering method using ZnO and Ga 2 O 3 targets were demonstrated. The results revealed that the resistivities of the GZO films reduced by at least two orders of magnitude after the thermal annealing. The reduction in resistivity could be attributed not only to the activation of Ga dopants and to the increase of electron mobility, but also to the enlargement of the grain size that occurred as a result of thermal annealing. The resistivity of GZO films reduced from 1.4 ϫ 10 −1 to 5.3 ϫ 10 −4 ⍀ cm after the films had undergone thermal annealing in nitrogen ambience with temperature ranging from 400 to 800°C. Additionally, the GZO films exhibited semiconducting conductivity and metallic conductivity in as-deposited and annealed samples ͑Ͼ600°C͒, respectively.

No abstract