Auger ionization in armchair-edge graphene nanoribbons

Free electron-hole (e-h) pair generation from excitons in armchair-edged graphene nanoribbons (AGNRs) is theoretically investigated. We consider the generation of free e-h pairs by the Auger ionization of exciton-exciton scattering. We calculate e-h pair-generation times in a tight-binding approximation and found that the times were of picosecond order for 1.2-2.5-nm-wide ribbons due to efficient scattering between excitons. Additionally, the environmental effects are found to largely influence the Auger ionization process. Our calculations reveal the important role of the Auger ionization of excitons in AGNRs. These findings are of crucial importance for the application of AGNRs to photoelectronic and optoelectronic devices.