Characterization of dopant density dependence on transmittance and resistance of ZnO films fabricated using spin-coating method

We fabricated aluminum (Al) and gallium (Ga) co-doped ZnO films by wet-process and evaluated their sheet resistances and transmission spectra. It was found that the sheet resistance becomes minimum when the content ratios of Al and Ga are 0.02 at the annealing temperature of 550 degree. Moreover, we found that the sheet resistance can be improved by performing the spin-coating and annealing twice. In this case, the transmission probability in the visible light regime is more than 90%. This result is a simple method to fabricate fine transparence conductive ZnO films.