posted on 2014-10-08, 00:00authored byThonimar
V. Alencar, Mychel G. Silva, Leandro M. Malard, Ana M. de Paula
Defects play a fundamental role in
the energy relaxation of hot
photoexcited carriers in graphene, thus a complete understanding of
these processes are vital for improving the development of graphene
devices. Recently, it has been theoretically predicted and experimentally
demonstrated that defect-assisted acoustic phonon supercollision,
the collision between a carrier and both an acoustic phonon and a
defect, is an important energy relaxation process for carriers with
excess energy below the optical phonon emission. Here, we studied
samples with defects optically generated in a controlled manner to
experimentally probe the supercollision model as a function of the
defect density. We present pump and probe transient absorption measurements
showing that the decay time decreases as the density of defect increases
as predicted by the supercollision model.