Onodera Momoko, Ataka Manabu, Zhang Yijin, Moriya Rai, Watanabe Kenji, Taniguchi Takashi, Toshiyoshi Hiroshi, Machida Tomoki
Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
ACS Appl Mater Interfaces. 2024 Nov 13;16(45):62481-62488. doi: 10.1021/acsami.4c05972. Epub 2024 Oct 31.
Two-dimensional (2D) materials can be transferred onto substrates with various surface structures, opening up multiple functions and applications for 2D materials in the form of suspended membranes. In this paper, we present a method for transferring exfoliated 2D crystal flakes from SiO substrates onto patterned substrates using a poly(vinyl chloride) (PVC) layer mounted on a polydimethylsiloxane (PDMS) stamp structure. 2D crystal flakes can be transferred onto various patterned structures such as grooves, round holes, and periodic hole or groove patterns. Our method can also be used to fabricate suspended van der Waals (vdW) heterostructures by assembling 2D crystal flakes on the PVC/PDMS stamp and then transferring them onto patterned substrates. The adhesiveness and curvature of the PVC/PDMS stamp were tuned, and a high successful transfer rate was realized due to the use of kamaboko-shaped (semicylindrical) PDMS and the addition of an appropriate amount of a high-viscosity plasticizer to the PVC layer. Taking advantage of this method, we demonstrate the facile fabrication, simply by transferring a vdW heterostructure onto an Au-coated groove substrate, of a suspended vdW field-effect transistor device with the carrier density tuned using ionic gating. This method enables the transfer of 2D crystal flakes and vdW heterostructures onto various patterned substrates, and hence it should help to advance suspended 2D materials research.
二维（2D）材料能够转移到具有各种表面结构的衬底上，从而以悬浮膜的形式为二维材料开启多种功能和应用。在本文中，我们提出了一种方法，使用安装在聚二甲基硅氧烷（PDMS）印章结构上的聚氯乙烯（PVC）层，将剥离的二维晶体薄片从SiO衬底转移到图案化衬底上。二维晶体薄片能够转移到各种图案化结构上，如凹槽、圆孔以及周期性的孔或凹槽图案。我们的方法还可用于通过在PVC/PDMS印章上组装二维晶体薄片，然后将它们转移到图案化衬底上来制造悬浮的范德华（vdW）异质结构。对PVC/PDMS印章的粘附性和曲率进行了调整，由于使用了卡玛波形状（半圆柱形）的PDMS并在PVC层中添加了适量的高粘度增塑剂，实现了较高的成功转移率。利用这种方法，我们展示了通过简单地将一个vdW异质结构转移到涂金的凹槽衬底上，就能轻松制造出一个通过离子门控调节载流子密度的悬浮vdW场效应晶体管器件。这种方法能够将二维晶体薄片和vdW异质结构转移到各种图案化衬底上，因此它应该有助于推动悬浮二维材料的研究。
