Kim Hyoung-Do, Naqi Muhammad, Jang Seong Cheol, Park Ji-Min, Park Yun Chang, Park Kyung, Nahm Ho-Hyun, Kim Sunkook, Kim Hyun-Suk
Department of Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea.
School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Mar 23;14(11):13490-13498. doi: 10.1021/acsami.1c24880. Epub 2022 Mar 8.
Zinc oxynitride (ZnON) has the potential to overcome the performance and stability limitations of current amorphous oxide semiconductors because ZnON-based thin-film transistors (TFTs) have a high field-effect mobility of 50 cm/Vs and exceptional stability under bias and light illumination. However, due to the weak zinc-nitrogen interaction, ZnON is chemically unstable─N is rapidly volatilized in air. As a result, recent research on ZnON TFTs has focused on improving air stability. We demonstrate through experimental and first-principles studies that the ZnF/ZnON bilayer structure provides a facile way to achieve air stability with carrier controllability. This increase in air stability (e.g., nitrogen non-volatilization) occurs because the ZnF layer effectively protects the atomic mixing between ZnON and air, and the decrease in the ZnON carrier concentration is caused by a shallow-to-deep electronic transition of nitrogen deficiency diffused from ZnON into the interface. Further, the TFT based on the ZnF/ZnON bilayer structure enables long-term air stability while retaining an optimal switching property of high field-effect mobility (∼100 cm/Vs) even at a relatively low post-annealing temperature. The ZnF/ZnON-bilayer TFT device exhibits fast switching behavior between 1 kHz and 0.1 MHz while maintaining a stable and clear switching response, paving the way for next-generation high-speed electronic applications.
氮氧化锌（ZnON）有潜力克服当前非晶氧化物半导体在性能和稳定性方面的局限，因为基于ZnON的薄膜晶体管（TFT）具有50 cm²/V·s的高场效应迁移率，并且在偏置和光照下具有出色的稳定性。然而，由于锌与氮之间的相互作用较弱，ZnON在化学上不稳定——氮在空气中会迅速挥发。因此，近期对ZnON TFT的研究集中在提高空气稳定性上。我们通过实验和第一性原理研究表明，ZnF/ZnON双层结构提供了一种实现空气稳定性并具备载流子可控性的简便方法。空气稳定性的提高（例如，氮不挥发）是因为ZnF层有效地保护了ZnON与空气之间的原子混合，而ZnON载流子浓度的降低是由从ZnON扩散到界面的氮缺陷从浅能级到深能级的电子跃迁引起的。此外，基于ZnF/ZnON双层结构的TFT即使在相对较低的退火温度下也能实现长期空气稳定性，同时保持高场效应迁移率（约100 cm²/V·s）的最佳开关特性。ZnF/ZnON双层TFT器件在1 kHz至0.1 MHz之间表现出快速开关行为，同时保持稳定且清晰的开关响应，为下一代高速电子应用铺平了道路。
