The First-Water-Layer Evolution at the Graphene/Water Interface under Different Electro-Modulated Hydrophilic Conditions Observed by Suspended/Supported Field-Effect-Device Architectures

Ming Hsiu Tsai, Yu Xuan Lu, Cheng Yu Lin, Chun Hsuan Lin, Chien Chun Wang, Che Men Chu, Wei Yen Woon, Chih Ting Lin

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Interfacial water molecules affect carrier transportation within graphene and related applications. Without proper tools, however, most of the previous works focus on simulation modeling rather than experimental validation. To overcome this obstacle, a series of graphene field-effect transistors (GFETs) with suspended (substrate-free, SF) and supported (oxide-supported, OS) configurations are developed to investigate the graphene-water interface under different hydrophilic conditions. With deionized water environments, in our experiments, the electrical transportation behaviors of the graphene mainly originate from the evolution of the interfacial water-molecule arrangement. Also, these current-voltage behaviors can be used to elucidate the first-water layer at the graphene-water interface. For SF-GFET, our experimental results show positive hysteresis in electrical transportation. These imply highly ordered interfacial water molecules with a separated-ionic distributed structure. For OS-GFET, on the contrary, the negative hysteresis shows the formation of the hydrogen-bond interaction between the interfacial water layer and the SiO2 substrate under the graphene. This interaction further promotes current conduction through the graphene/water interface. In addition, the net current-voltage relationship also indicates the energy required to change the orientation of the first-layer water molecules during electro-potential change. Therefore, our work gives an insight into graphene-water interfacial evolution with field-effect modulation. Furthermore, this experimental architecture also paves the way for investigating 2D solid-liquid interfacial features.

Original languageEnglish
Pages (from-to)17019-17028
Number of pages10
JournalACS Applied Materials and Interfaces
Volume15
Issue number13
DOIs
StatePublished - 5 Apr 2023

Keywords

  • graphene field-effect transistor
  • graphene/water Interface
  • hydrogen-bounded network structure
  • hysteresis effect
  • interfacial water molecules
  • suspended graphene

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