Gallium-Doped Zinc Oxide Nanoparticle Thin Films as\nTransparent Electrode Materials with High Conductivity

Abstract

Gallium-doped zinc\noxide (GZO) nanoparticles (NPs) have been synthesized\nby a solvothermal synthesis method using gallium chloride and zinc\nchloride as precursors in anhydrous methanol along with bases. Systematic\ninvestigations have revealed that H₂O, formed through the\ncondensation of metal hydroxides to obtain GZO NPs, not only enhances\nthe production of layered compounds as byproducts but also accelerates\nOstwald ripening to reduce the amount of doped gallium ions. To overcome\nH₂O generation during NP growth, we first applied sodium\nmethoxide (NaOMe) as a base for the synthesis of GZO NPs. As a result,\nhigh-performance GZO NPs were successfully obtained in a single phase,\nand the mean particle size of the GZO NPs was controlled from 10 to\n35 nm by changing the molar ratio of the sodium hydroxide (NaOH) and\nNaOMe in the reaction mixture. We further applied the obtained GZO\nNPs to prepare GZO NP-based transparent conductive metal oxide (TCO)\nfilms using an NP-mist deposition strategy as our developed NP-coating\nmethod on substrates. The resistivity and transparency of the deposited\nGZO thin films were compared with those of conventional thin films\nprepared by a dispersion coating method, showing that NP-mist deposition\nis a promising method for fabricating high-performance GZO NP-based\nTCO thin films on substrates under mild atmospheric conditions.