Fine band gap modulation effects of aGNRs by an organic functional group: a first-principles study

We report a first-principles study of the electronic structure of functionalized graphene nanoribbon (aGNRs-f) by an organic functional group (CH2C6H5) and find that CH2C6H5 functionalized group does not produce any electronic states in the gap and the band gap is direct. By changing both the density of the organic functional group and the width of the aGNRs-f, a band gap tuning exhibits a fine three-family behaviour through the side effect. Meanwhile, the carriers at the conduction band minimum and the valence band maximum are located in both CH2C6H5 and aGNR regions when the density of CH2C6H5 is big, while they distribute dominantly in aGNR conversely. The fine band gap modulation effects make aGNRs-f good candidates with high quantum efficiency and a significantly wider wavelength range from 750 to 93 924 nm for lasers, light-emitting diodes and photodetectors due to the direct band gap and small carrier effective masses. (paper)