  A specific structure of doped graphene with substituted silicon impurity is
introduced and ab. initio density-functional approach is applied for energy
band structure calculation of proposed structure. Using the band structure
calculation for different silicon sites in the host graphene, the effect of
silicon concentration and unit cell geometry on the bandgap of the proposed
structure is also investigated. Chemically silicon doped graphene results in an
energy gap as large as 2eV according to DFT calculations. As we will show, in
contrast to previous bandgap engineering methods, such structure has
significant advantages including wide gap tuning capability and its negligible
dependency on lattice geometry.
