In-Ga-Zn-O amorphous thin films for transparent electronics

In-Ga-Zn-O thin films fabricated by reactive RF magnetron sputtering have been investigated for their compositional, structural, morphological, electrical and optical properties. All resulting films present the amorphous microstructure, and root mean square roughness below 0.6 nm. The variation of the oxygen content in the deposition atmosphere from 0% to 0.9% results in the formation of a-IGZO thin films consisting of 15-29% indium, 16-28% gallium, 10-13% zinc and 30-60% oxygen, which significantly differs from the InGaZnO4 target composition. IGZO thin films present the transmittance in range of 75% to 90% for VIS-NIR wavelengths. Mechanism of free electrons generation via oxygen vacancies formation is proposed to determine the relation between oxygen content in the deposition atmosphere and the transport properties of the IGZO of the thin films.

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