【公開日：2024.07.25】【最終更新日：2024.05.16】

課題データ / Project Data

課題番号 / Project Issue Number

23UT1073

利用課題名 / Title

2D-materials based nanochannels

利用した実施機関 / Support Institute

東京大学 / Tokyo Univ.

機関外・機関内の利用 / External or Internal Use

内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)

技術領域 / Technology Area

【横断技術領域 / Cross-Technology Area】（主 / Main）加工・デバイスプロセス/Nanofabrication（副 / Sub）-

【重要技術領域 / Important Technology Area】（主 / Main）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion（副 / Sub）次世代ナノスケールマテリアル/Next-generation nanoscale materials

キーワード / Keywords

μTAS、流路デバイス,電子線リソグラフィ/ EB lithography,膜加工・エッチング/ Film processing/etching,環境発電/ Energy Harvesting,原子層薄膜/ Atomic layer thin film,ナノシート/ Nanosheet

利用者と利用形態 / User and Support Type

利用者名（課題申請者）/ User Name (Project Applicant)

MOUTERDE Timothee

所属名 / Affiliation

東京大学大学院工学系研究科機械工学専攻

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

利用形態 / Support Type

（主 / Main）機器利用/Equipment Utilization（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

UT-503：超高速大面積電子線描画装置
UT-600：汎用ICPエッチング装置

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

Van der Waals assembly of two-dimensional (2D) materials has provided us with a great way to create nano-scale to ångström-scale channels with atomically smooth surfaces. Nanofluidics can be used for osmotic energy harvesting (salinity gradient across membrane). In this project, we transfer and stack graphene or hBN flakes into a three-layer structure, in which the middle layer is patterned to many parallel strips, so that nanochannels can form between the bottom and the top layers (Figure 1). In this process, the most critical procedure is the patterning of the middle layer, realized by electron beam lithography (EBL) followed by Plasma etching. Fabricated nanochannels are used to investigate the transport of water molecules and ions inside the nanochannels made of hBN and graphene. 

実験 / Experimental

PMMA (950A4) was spin-coated on the Si/SiO₂ substrates with graphene or hBN flakes. Then they were exposed to electron beams in F7000S-VD02 to write parallel lines. The optimal EB dose is found to be 750 uC/cm²after several tests. Then they are developed in a mixture of MIBK and IPA (1:3) for 1 min and rinsed in IPA twice. After this EBL process, many parallel channels with a width of 100-200 nm were created in the PMMA on top of those chosen 2D material flakes. Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) processes were done to pattern graphene or hBN flakes into strips by using PMMA as a mask. We used the General purpose ICP etching machine CE-300I to do that. For graphene etching, the O₂ was used and for hBN etching, CHF₃ and O₂ mixture was used. Finally, the PMMA layer was removed by remover PG, and AFM was used to check the width and depth of etched channels and the cleanliness of the surfaces. 

結果と考察 / Results and Discussion

Figure 2 shows an hBN flake that was patterned into strips with a width of 300 nm and a space of 200 nm. The thickness and the distances between patterned strips of the middle layer define the height and the width of nanochannels. So the etching rates for graphene and hBN were checked by AFM. Figure 3 and Figure 4 show the dimensions of etched channels on graphene and hBN separately when both of them are etched for 10 s. It can be found that the width of the channels is a little larger than the design because of the relatively high EB dose and etching in the horizontal plane. For graphene etched by O₂, the etching rate is about 3 nm/s. For hBN etched by CHF₃ and O₂ mixture, the etching rate is about 3.3 nm/s. 

図・表・数式 / Figures, Tables and Equations

Figure 1　 Process for a three-layer structure made by graphene or hBN flakes.

Figure 2 An hBN flake that was patterned into strips with a width of 300 nm and a space of 200 nm.

Figure 3 The dimensions of etched channels on graphene which is etched for 10 s.

Figure 4 The dimensions of etched channels on hBN which is etched for 10 s.

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

Bhardwaj, A., Surmani Martins, M.V., You, Y. et al. Fabrication of angstrom-scale two-dimensional channels for mass transport. Nat Protoc 19, 240–280 (2024).

成果発表・成果利用 / Publication and Patents

論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

特許 / Patents

特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件