Selective Amorphization of Oxide Surface by Introducing Hydrogen Impurity

The oxide semiconductors have been widely used in various electronic devices such as flat panel displays and solar cells. Especially, crystalline oxide semiconductors are attracting industrial interest due to their high electron mobility that arises from the well-aligned periodic array of the constituent elements. However, the rough surface morphology resulting from the grain growth triggers severe drawbacks in their thin-film applications. In this study, we demonstrate a surface amorphization of the oxide semiconductor thin film by introducing hydrogen gas during the deposition process. The surface of the crystalline In–Sn–O thin film is selectively amorphized, allowing for smooth surface morphology without any degradation of the electrical properties. In addition, the progressive surface amorphization offers the tunability of the work function, leading to the improved power conversion efficiency of the thin-film solar cell. The present study provides a tractable way to achieve the smooth surface of the crystalline thin films.