  The Young's modulus of graphene is estimated by measuring the strain applied
by a pressure difference across graphene membranes using Raman spectroscopy.
The strain induced on pressurized graphene balloons can be estimated directly
from the peak shift of the Raman G band. By comparing the measured strain with
numerical simulation, we obtained the Young's modulus of graphene. The
estimated Young's modulus values of single- and bi-layer graphene are 2.4\pm0.4
TPa and 2.0\pm0.5 TPa, respectively.
