title: Carrier cooling in colloidal quantum wells.
abstract: It has recently become possible to chemically synthesize atomically flat semiconductor nanoplatelets with monolayer-precision control over the platelet thickness. It has been suggested that these platelets are quantum wells; that is, carriers in these platelets are confined in one dimension but are free to move in the other two dimensions. Here, we report time-resolved photoluminescence and transient-absorption measurements of carrier relaxation that confirm the quantum-well nature of these nanomaterials. Excitation of the nanoplatelets by an intense laser pulse results in the formation of a high-temperature carrier population that cools back down to ambient temperature on the time scale of several picoseconds. The rapid carrier cooling indicates that the platelets are well-suited for optoelectronic applications such as lasers and modulators.
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States. pelton@anl.gov
authors.forename: Matthew
authors.initials: M
authors.lastname: Pelton
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ithurria
authors.forename: Richard D
authors.initials: RD
authors.lastname: Schaller
authors.forename: Dmitriy S
authors.initials: DS
authors.lastname: Dolzhnikov
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Talapin