Hot carrier relaxation in CdTe via phonon–plasmon modes

Abstract

Carrier and lattice dynamics of laser excited CdTe was studied by time-resolved reflectivity for excitation fluences spanning about three orders of magnitude, from 0.064 to 6.14 mJ cm. At fluences below 1 mJ cm the transient reflectivity is dominated by the dynamics of hybrid phonon-plasmon modes. At fluences above 1 mJ cm the time-dependent reflectivity curves show a complex interplay between band-gap renormalization, band filling, carrier dynamics and recombination. A framework that accounts for such complex dynamics is presented and used to model the time-dependent reflectivity data. This model suggests that the excess energy of the laser-excited hot carriers is reduced much more efficiently by emitting hybrid phonon-plasmon modes rather than bare longitudinal optical phonons.

Slow Cooling of Hot Polarons in Halide Perovskite Solar Cells

“…Heat diffuses from MAPI on the order of 100 ps, while for other conductivities, the process is much faster, on the order of 100 fs. This is in agreement with reported experimental values: ref (MAPI) ref (CdTe), and ref (GaAs). Note that at short time scales, measurements of hot carrier cooling in MAPI and CsPbI 3 (κ = 0.5, green dashed line) may appear linear due to the slower exponential decay.…”