{"id":578,"date":"2026-09-09T13:24:08","date_gmt":"2026-09-09T13:24:08","guid":{"rendered":"https:\/\/twistronics.c2n.universite-paris-saclay.fr\/?page_id=578"},"modified":"2026-09-10T05:42:02","modified_gmt":"2026-09-10T05:42:02","slug":"exfoliation","status":"publish","type":"page","link":"https:\/\/twistronics.c2n.universite-paris-saclay.fr\/?page_id=578","title":{"rendered":"Exfoliation"},"content":{"rendered":"\n

Cleanly exfoliated 2D materials are the foundation of high-quality van der Waals heterostructures. There are plenty of tricks that can improve the process, but ultimately, nothing replaces experience. Of course, using the right exfoliation tape and a clean substrate also goes a long way toward achieving reliable, high-quality flakes.<\/p>\n\n\n

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Exfoliated flakes of hexagonal boron nitride (hBN)<\/strong>, graphene<\/strong>, and graphite<\/strong> (from left to right) on a silicon substrate with a 285 nm thermally grown SiO\u2082<\/strong> layer.<\/strong><\/figcaption><\/figure>\n<\/div>\n\n\n

Choose your tape:<\/strong> This has been a long-standing debate in the 2D materials community, with some research groups using blue cleanroom tape and others relying on regular Scotch tape. In practice, there is no clear consensus that one is universally better than the other, as both approaches can produce clean, high-quality flakes when properly handled.<\/p>\n\n\n\n

As with many aspects of exfoliation, experience plays a key role. It is worth testing different tapes and developing your own process, as the results can depend on several factors, including the humidity and temperature of the room where the exfoliation is performed.<\/p>\n\n\n

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Photograph showing a selection of commercially available tapes used for exfoliation. Nitto tapes:<\/strong> (A) ELP BT-130E-SL, (B) ELP BT-150E-KL, and (C) ELP BT-50E-FR; alongside Ultron tapes:<\/strong> (D) 1007R-6.0 and (E) 1009R-6.0. Adapted from Daniel Terry’s PhD thesis<\/a><\/strong><\/figcaption><\/figure>\n<\/div>\n\n\n

Heating technique:<\/strong> To obtain large-area monolayer and bilayer graphene, as well as other high-quality 2D materials, it is highly recommended to use the approach developed in this article<\/a>. In brief, the Si\/SiO\u2082 substrates should first be cleaned using a gentle oxygen plasma<\/strong> (~20 s)<\/strong> treatment before bringing the exfoliation tape into contact with the substrate. Once the tape carrying the exfoliated material is placed in contact with the substrate, the sample is heated on a hot plate at approximately 105 \u00b0C for ~4 minutes<\/strong>. After heating, allow the sample to cool down before carefully peeling off the tape, leaving the exfoliated flakes on the substrate.<\/p>\n\n\n\n

BN exfoliation:<\/strong> when relatively thick flakes of BN (30 nm – 80 nm) are desired, the process is similar to the one described above, but without heating the substrate before peeling off the tape<\/strong>. Avoiding the heating step generally results in cleaner BN flakes improving the quality of the exfoliated material.<\/p>\n\n\n\n

Pro tips:<\/strong><\/p>\n\n\n\n