2023 ACS Applied Materials & Interfaces Original
Engineering Interface Defects and Interdiffusion at the Degenerate Conductive In2O3/Al2O3 Interface for Stable Electrodes in a Saline Solution
Zetao Zhu*, Takao Yasui*, Xixi Zhao, Quanli Liu, Shu Morita, Yan Li, Akira Yonezu, Kazuki Nagashima, Tsunaki Takahashi, Minoru Osada, Ryotaro Matsuda, Takeshi Yanagida, and Yoshinobu Baba*,2023, 15, 30
A low-temperature Al2O3 deposition process provides a simplified method to form a conductive two-dimensional electron gas (2DEG) at the metal oxide/Al2O3 heterointerface. However, the impact of key factors of the interface defects and cation interdiffusion on the interface is still not well understood. Furthermore, there is still a blank space in terms of applications that go beyond the understanding of the interface’s electrical conductivity. In this work, we carried out a systematic experimental study by oxygen plasma pretreatment and thermal annealing post-treatment to study the impact of interface defects and cation interdiffusion at the In2O3/Al2O3 interface on the electrical conductance, respectively. Combining the trends in electrical conductance with the structural characteristics, we found that building a sharp interface with a high concentration of interface defects provides a reliable approach to producing such a conductive interface. After applying this conductive interface as electrodes for fabricating a field-effect transistor (FET) device, we found that this interface electrode exhibited ultrastability in phosphate-buffered saline (PBS), a commonly used biological saline solution. This study provides new insights into the formation of conductive 2DEGs at metal oxide/Al2O3 interfaces and lays the foundation for further applications as electrodes in bioelectronic devices.