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Tuning the plasmon resonance and work function of laser-scribed chemically doped graphene

Aug 30, 2017

Anis, Badawi, A. Abouelsayed, Amany M. Sawy, and Ahmed SG Khalil.

Here, we present terahertz spectroscopy study on laser scribed graphene (LSG) doped with monovalent Na+ cations (LSG/MNCs), silver nanoparticles (LSG/SNPs), and silver nanowires (LSG/SNWs), in the frequency range from 0.06 to 3 THz. The terahertz absorption peaks observed at ≈ 1.98, 2.06, 2.73, and 3.06 THz are attributed to the collective oscillations of free carriers in LSG, LSG/MNCs, LSG/SNPs, and LSG/SNWs, respectively. The plasmon peak position and Fermi energy Ef of LSG doped samples are shifted to higher energy compared to undoped LSG indicating the n-doping of graphene. The σdc and the charges concentration n show higher values in case of LSG/SNWs compared to other doped samples. This is mainly because silver nanowires create conducting paths between the neighboring graphene sheets. The charge density n of the LSG and LSG doped samples versus Ef, scales as n1/4, illustrates power-law behavior which is the signature of the two-dimensional massless Dirac electrons.