2016/06/22 by Fabiana Francesca Settembrini, Francesco Colangelo, Settembrini, Fabiana Francesca +17
Materials Science · Engineering · #Diamond and Carbon-based Materials Research #Graphene research and applications #Advanced MEMS and NEMS Technologies
paper · pdf · doi:10.48550/arxiv.1606.06995
We use micro-Raman spectroscopy to study strain profiles in graphene monolayers suspended over SiN membranes micropatterned with holes of non-circular geometry. We show that a uniform differential pressure load ΔP over elliptical regions of free-standing graphene yields measurable deviations from hydrostatic strain conventionally observed in radially-symmetric microbubbles. The top hydrostatic strain ε we observe is estimated to be ≈0.7% for ΔP = 1 \rm bar in graphene clamped to elliptical SiN holes with axis 40 and 20 \rm μm. In the same configuration, we report a G_± splitting of 10 \rm cm-1 which is in good agreement with the calculated anisotropy Δε ≈ 0.6% for our device geometry. Our results are consistent with the most recent reports on the Grüneisen parameters. Perspectives for the achievement of arbitrary strain configurations by designing suitable SiN holes and boundary clamping conditions are discussed.