[20p-221B-1~11] 4.5 Nanocarbon and 2D Materials

▼ [20p-221B-5] Molecular screening effects on exciton-carrier interactions in suspended carbon nanotubes

〇Shunsuke Tanaka¹, Takushi Uda^1,2, Yuichiro Kato¹ (1.RIKEN, 2.Univ. of Tokyo)

Keywords:carbon nanotube, molecular adsorption

We investigate the molecular screening effects on trion binding energies and carrier-induced photoluminescence quenching in suspended carbon nanotubes using field-effect transistor structures. Comparing the gate voltage dependent photoluminescence from nanotubes before and after molecular adsorption, we find differences in the emission energies as well as the voltage dependence. The adsorption induced changes in the emission energies indicate that trion binding energies are largely modified by the molecules. Furthermore, the unquenched voltage region for the bright exciton photoluminescence are narrower for the adsorbed state, which can be explained by a decrease in the electronic bandgap by molecular screening. We also find a shift of the charge neutrality point, which could arise from changes in the chemical potential for the nanotubes or the work function of the contact metals.