Enhancement of island size by dynamic substrate disorder in simulations of graphene growth
| Autor: | Gavin R. Bell, David Quigley, Peter Brommer, Gwilym Enstone |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Break-Up Graphene Monte Carlo method General Physics and Astronomy Nanotechnology 02 engineering and technology Surface finish Substrate (electronics) Island growth 010402 general chemistry 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences 0104 chemical sciences law.invention Chemical physics law QD Destabilisation Physical and Theoretical Chemistry 0210 nano-technology QC |
| Zdroj: | Physical chemistry chemical physics : PCCP. 18(22) |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | We demonstrate a new mechanism in the early stages of sub-monolayer epitaxial island growth, using Monte Carlo simulations motivated by experimental observations on the growth of graphene on copper foil. In our model, the substrate is “dynamically rough”, by which we mean (i) the interaction strength between Cu and C varies randomly from site to site, and (ii) these variable strengths themselves migrate from site to site. The dynamic roughness provides a simple representation of the near-molten state of the Cu substrate in the case of real graphene growth. Counterintuitively, the graphene island size increases when dynamic roughness is included, compared to a static and smooth substrate. We attribute this effect to destabilisation of small graphene islands by fluctuations in the substrate, allowing them to break up and join larger islands which are more stable against roughness. In the case of static roughness, when process (ii) is switched off, island growth is strongly inhibited and the scale-free behaviour of island size distributions, present in the smooth-static and rough-dynamic cases, is destroyed. The effects of the dynamic substrate roughness cannot be mimicked by parameter changes in the static cases. |
| Databáze: | OpenAIRE |
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