Direct Imaging of Charged Impurity Density in Common Graphene Substrates
| Autor: | William G. Cullen, Kenji Watanabe, Michael S. Fuhrer, Takashi Taniguchi, Kristen M. Burson, Cory Dean, Philip Kim, Shaffique Adam |
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| Rok vydání: | 2013 |
| Předmět: |
Kelvin probe force microscope
Materials science Plane (geometry) Graphene Orders of magnitude (temperature) Mechanical Engineering Charge density Bioengineering Charge (physics) General Chemistry Condensed Matter Physics Molecular physics law.invention law Metastability Cathode ray General Materials Science Atomic physics |
| Zdroj: | Nano Letters. 13:3576-3580 |
| ISSN: | 1530-6992 1530-6984 |
| DOI: | 10.1021/nl4012529 |
| Popis: | Kelvin probe microscopy in ultrahigh vacuum is used to image the local electrostatic potential fluctuations above hexagonal boron nitride (h-BN) and SiO2, common substrates for graphene. Results are compared to a model of randomly distributed charges in a two-dimensional (2D) plane. For SiO2, the results are well modeled by 2D charge densities ranging from 0.24 to 2.7 × 10(11) cm(-2), while h-BN displays potential fluctuations 1-2 orders of magnitude lower than SiO2, consistent with the improvement in charge carrier mobility for graphene on h-BN compared to SiO2. Electron beam exposure of SiO2 increases the charge density fluctuations, creating long-lived metastable charge populations of ~2 × 10(11) cm(-2) at room temperature, which can be reversed by heating. |
| Databáze: | OpenAIRE |
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