Copper iodide and oxide semiconductor thin films patterned by spray-spin coating for fabricating complementary inverters: Improving stability with passivation layers

• Published in: Applied surface science 2023-01, Vol.608, p.155081, Article 155081
• Main Authors: Lee, Kyumin, Gyu Oh, Jong, Kim, Doyeon, Baek, Jisu, Ho Kim, In, Nam, Sooji, Jeong, Yong Jin, Jang, Jaeyoung
• Format: Article
• Language: English
• Subjects: Complementary inverters; Copper iodide; P-type thin-film transistors; Passivation; Solution process; Spray-spin coating
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.155081

[Display omitted] •Zn-doped CuI (Zn:CuI) were patterned using a spray-spin coating method.•CYTOP passivation layer controlled the oxygen penetration into the Zn:CuI films.•The CYTOP-passivated Zn:CuI TFT showed high performance and reliable operation.•Complementary inverter comprising In2O3/ZnO and Zn:CuI was demonstrated on a single wafer. Recently, copper iodide (CuI) has been studied as a solution-processed p-type semiconductor owing to its high hole mobility and low-temperature processability. With the development of the field in this solution-processed inorganic semiconductor, it has become increasingly necessary to integrate the p-type thin-film transistors (TFTs) into a complementary inverter using a simple solution-based patterning method. However, compared to the n-type counterpart, it remains a challenge to pattern the p-type inorganic TFTs while maintaining reliable performances. In this study, Zn-doped CuI (Zn:CuI) were patterned in a simple manner by combining spin and spray coating, namely “spray-spin coating,” to fabricate p-type TFTs. The device stability of the spray-spin-coated Zn:CuI TFTs was ensured by treating hydrophobic fluoropolymer, CYTOP, as a passivation layer. Owing to the blocking of oxygen penetration at the CYTOP layer, which was confirmed by the chemical binding energy states of the Zn:CuI thin film, the resulting devices exhibited enhanced electrical characteristics while maintaining low off-state current and normal threshold voltage. Finally, via spray-spin coating, complementary inverters comprising n-type In2O3/ZnO bilayer and p-type Zn:CuI semiconductors were successfully fabricated on a single wafer, demonstrating a robust switching operation.