posted on 2024-01-04, 16:09authored byNicole Spanedda, Chandler Martin, Kevin Mesta, Arindam Chakraborty
Inverse photoemission (IPE) is a radiative electron capture
process
where an electron is transiently captured in the conduction band (CB)
followed by intraband de-excitation and spontaneous photon emission.
IPE in quantum dots (QDs) bypasses optical selection rules for populating
the CB and provides insights into the capacity for electron capture
in the CB, the propensity for spontaneous photon emission, intraband
transition energies where both initial and final states are in the
CB, and the generation of photons with frequencies lower than the
bandgap. Here, we demonstrate using time-dependent perturbation theory
that judicious application of electric fields can significantly enhance
the IPE transition in QDs. For a series of CdSe, CdS, PbSe, and PbS
QDs, we present evidence of field-induced enhancement of IPE intensities
(188% for Cd54Se54), field-dependent control
of emitted photon frequencies (Δω = 0.73
eV for Cd54Se54), and enhancement of light–matter
interaction using directed Stark fields (103% for Cd54Se54).