Rahpeima Soraya, Dief Essam M, Ciampi Simone, Raston Colin L, Darwish Nadim
School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia.
Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia.
ACS Appl Mater Interfaces. 2021 Aug 18;13(32):38799-38807. doi: 10.1021/acsami.1c06495. Epub 2021 Aug 3.
The presence of a natural silicon oxide (SiO) layer over the surface of silicon (Si) has been a roadblock for hybrid semiconductor and organic electronics technology. The presence of an insulating oxide layer is a limiting operational factor, which blocks charge transfer and therefore electrical signals for a range of applications. Etching the SiO layer by fluoride solutions leaves a reactive Si-H surface that is only stable for few hours before it starts reoxidizing under ambient conditions. Controlled passivation of silicon is also of key importance for improving Si photovoltaic efficiency. Here, we show that a thin layer of graphene oxide (GO) prevents Si surfaces from oxidation under ambient conditions for more than 30 days. In addition, we show that the protective GO layer can be modified with molecules enabling a functional surface that allows for further chemical conjugation or connections with upper electrodes, while preserving the underneath Si in a nonoxidized form. The GO layer can be switched electrochemically to reduced graphene oxide, allowing the development of a dynamic material for molecular electronics technologies. These findings demonstrate that 2D materials are alternatives to organic self-assembled monolayers that are typically used to protect and tune the properties of Si and open a realm of possibilities that combine Si and 2D materials technologies.
硅（Si）表面天然存在的氧化硅（SiO）层一直是混合半导体和有机电子技术发展的障碍。绝缘氧化层的存在是一个限制运行的因素，它会阻碍电荷转移，进而影响一系列应用中的电信号传输。用氟化物溶液蚀刻SiO层会留下具有反应活性的Si-H表面，该表面在环境条件下仅能稳定存在几个小时，之后便开始重新氧化。对硅进行可控钝化对于提高硅光伏效率也至关重要。在此，我们表明，一层氧化石墨烯（GO）可防止硅表面在环境条件下氧化超过30天。此外，我们还表明，保护性的GO层可以用分子进行修饰，从而形成一个功能性表面，该表面允许进一步的化学共轭或与上电极连接，同时使下层硅保持非氧化形式。GO层可以通过电化学方法转变为还原氧化石墨烯，从而为分子电子技术开发出一种动态材料。这些发现表明，二维材料可替代通常用于保护和调节硅性能的有机自组装单分子层，并开启了一个将硅和二维材料技术相结合的可能性领域。
