Photoexcited carrier dynamics and impact-excitation cascade in graphene

Justin C. W. Song, Klaas J. Tielrooij, Frank H. L. Koppens, Leonid S. Levitov
2013 Physical Review B  
Photo-excitation in solids can trigger a cascade in which multiple particle-hole excitations are generated. We analyze the carrier multiplication cascade of impact excitation processes in graphene and show that the number of pair excitations has a strong dependence on doping, which makes carrier multiplication gate-tunable. We also predict that the number of excited pairs as well as the characteristic time of the cascade scale linearly with photo-excitation energy. These dependences, as well as
more » ... ndences, as well as sharply peaked angular distribution of pair excitations, provide clear experimental signatures of carrier multiplication.
doi:10.1103/physrevb.87.155429 fatcat:cah25duycvd5tnt2lcb5dzhxdy