ABSTRACT
Transparent Conductive Oxide (TCO) has been widely used in industries of solar cells, flat panel display, organic light emitting diode and automobile [1-4]. Tin doped Indium Oxide (ITO) is the candidate in TCO that is frequently used due to excellent electrical and optical properties. Indium in ITO is rare in earth that raises material cost and toxins that produces health risk for human [5]. The substitute of ITO is therefore needed. Zinc oxide in TCO is cheap and non-toxic. The impurity of IIIA group doped zinc oxide like Aluminum doped Zinc Oxide (AZO) and Gallium doped Zinc Oxide (GZO) have been often reported. Good electrical and optical properties of AZO were reported. The AZO has better stability than ITO under atmosphere of hydrogen plasma [6, 7]. Gallium is more inert to oxidation compared to aluminum [8, 9]. Gallium and Aluminum co-doped Zinc Oxide (GAZO) films were fabricated to expect that GAZO can have the advantages of both AZO and GZO [10, 11]. Hydrogen plasma treatment can increase the carrier concentration and mobility of AZO films due to it producing shallow hydrogen donors and removing the oxygen adsorbed on grain boundaries [12-14].
