Direct Ablation of Aluminum-Doped Zinc Oxide Thin Films for Electrode Patterning by Optimization of Laser Beam Conditions

A Q-switched diode-pumped neodymium-doped yttrium vanadate (Nd:YVO4, lambda = 1064 nm) laser was used for direct ablation of aluminum-doped zinc oxide (AZO) films sputtered on glass and flexible polyethylene terephthalate (PET) substrates for developing low cost simple patterning process. AZO film on the PET substrate showed larger etching widths and a lower ablation threshold energy compared with those on the glass substrate, owing to lower thermal conductivity of the flexible substrate compared with that of the glass substrate. In certain laser beam conditions with overlap rates higher than 78%, AZO debris were observed on glass substrate instead of the etched line, because the removal process for evaporating the melted AZO layer could not be completed owing to the overlap with consecutive melting process. For an overlap rate with high scanning speed and low repetition rate of laser beam, it was possible to obtain a completely etched line on AZO film on glass substrate. The laser patterned AZO electrodes showed a relatively high current density for the application to various electronic devices.