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http://hdl.handle.net/1843/44021| Type: | Artigo de Evento |
| Title: | Observation of moiré superlattices on twisted bilayer graphene by scanning microwave impedance microscopy |
| Authors: | Douglas August Alexander Ohlberg Cássio Gonçalves do Rego Ado Jorio de Vasconcelos Gilberto Medeiros Ribeiro Andreij de Carvalho Gadelha Diego Camilo Tami López Eliel Gomes da Silva Neto Daniel A. Miranda Jéssica Santos Lemos Fabiano Costa Santana Leonardo Cristiano Campos Jhonattan Córdoba Ramírez |
| Abstract: | In the emerging field of twistronics, new electronic devices based on bilayer graphene have shown distinct electronic properties that depend on the rotational misalignment of one crystalline layer with respect to another. Given present methods of preparing these bilayers, there is always some uncertainty in the actual versus targeted twist angle of a specific bilayer that can only be resolved by measuring the moiré patterns that are unique to a specific twist angle. Traditional methods enabling such a measurement, Transmission Electron Microscopy and Scanning Tunneling Microscopy, impose serious restrictions on the types of substrates supporting the bilayers, which, in turn, constrains the subsequent fabrication of any devices. We report here a new, non-destructive method to measure moiré patterns of bilayer graphene deposited on any smooth substrate, using the scanning probe technique known as scanning microwave impedance microscopy (sMIM) which enables the simultaneous generation of localized topography, capacitance and conductance images with nanometer scale resolution1. Moiré patterns were observed in samples prepared on various substrates with twist angles ranging from 0.02 to 6.7 degrees, beyond which the moiré patterns are too small to be resolved by the sMIM probes. We present some possible reasons for the various contrast mechanisms. Addressing the problem of variations across a bilayer surface due to localized moiré distortions that result from the tensile and shear forces involved in transferring a twisted bilayer to a substrate, we demonstrate how sMIM can precisely map the twist angle distribution across the film, and enable direct device and circuit routing. |
| Subject: | Grafeno Microscopia |
| language: | eng |
| metadata.dc.publisher.country: | Brasil |
| Publisher: | Universidade Federal de Minas Gerais |
| Publisher Initials: | UFMG |
| metadata.dc.publisher.department: | ENG - DEPARTAMENTO DE ENGENHARIA ELÉTRICA ICX - DEPARTAMENTO DE CIÊNCIA DA COMPUTAÇÃO ICX - DEPARTAMENTO DE FÍSICA |
| Rights: | Acesso Restrito |
| metadata.dc.identifier.doi: | https://doi.org/10.1117/12.2570651 |
| URI: | http://hdl.handle.net/1843/44021 |
| Issue Date: | 2020 |
| metadata.dc.url.externa: | https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11465/114650J/Observation-of-moir%C3%A9-superlattices-on-twisted-bilayer-graphene-by-scanning/10.1117/12.2570651.full?webSyncID=026d873b-139a-c658-4444-37c22323c473&sessionGUID=7981396&SSO=1 |
| metadata.dc.relation.ispartof: | SPIE Nanoscience + Engineering |
| Appears in Collections: | Artigo de Evento |
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