Improvement in the Optical and Electrical Properties of Ga-doped Zinc-oxide Films by Using Nano-imprinted Pattern Arrays and Post-annealing

The effects of nano-imprinted arrays and post-annealing on the optical and the electrical properties of sputtered Ga-doped zinc-oxide (GZO) films were intensively investigated to develop suitable electrodes for photonic applications. We fabricated nano-structures with a GZO circular pattern with a diameter of 250 nm by using UV nano-imprinting lithography and the lift-off process. The nano-structured GZO/glass substrate showed a high optical transmittance of 91.0% at a wavelength of 550 nm, which was increased by about 2.2% compared to that of unprocessed GZO/glass. Then nano-structured GZO/glass substrate was rapidly annealed under different conditions to acquire a high optical transmittance and a low resistivity. The optimized nano-structured GZO film postannealed at 400 ◦C showed the highest optical transmittance of 92.0% and an improved resistivity of 1.3 × 10−3 Ω·cm.