Impact of active layer thickness in thin-film transistors based on Zinc Oxide by ultrasonic spray pyrolysis

• Application of ZnO films by ultrasonic spray pyrolysis at 200 °C in TFTs is demonstrated.
• Thicker active layer results in better output characteristics (Ids vs. Vds).
• Thinner active layer results in better transfer characteristics such as on/off-current ratio.

In this work, the preparation of Zinc Oxide (ZnO) films by ultrasonic spray pyrolysis at low-temperature and its application in thin-film transistors (TFTs) are presented, as well, the impact of the active layer thickness and gate dielectric thickness in the electrical performance of the ZnO TFTs. A thinner active layer resulted in better transfer characteristics such as higher on/off-current ratio, while a thicker active layer resulted in better output characteristics. The ZnO films were deposited from 0.2 M precursor solution of Zinc acetate in methanol, using air as carrier gas on a hotplate at 200 °C. The ZnO films obtained at 200 °C were characterized by optical transmittance, Photoluminescence spectroscopy and X-ray diffraction.