  Understanding the origin of hot carrier relaxation in nanowires (NWs) with
one-dimensional (1D) geometry is significant for designing efficient hot
carrier solar cells with such nanostructures. Here, we study the influence of
Auger heating and Shockley-Read-Hall recombination on hot carrier dynamics of
catalyst-free InGaAs-InAlAs core-shell NWs. Using steady-state and
time-resolved photoluminescence (PL) spectroscopy the dependencies of hot
carrier effects on the degree of confinement of photo-generated carriers
induced by the nanowire diameter are determined at different lattice
temperatures. Analysis of excitation-power dependent data and
temperature-dependent PL linewidth broadening reveal that at low temperatures,
strong Auger recombination and phonon-bottleneck are responsible for hot
carrier effects. Our analysis gives also insights into electron-phonon and
ionized impurity scattering, showing opposing trends with NW diameter, and it
allows to estimate the Fr\"ohlich coupling constant for the InGaAs NWs.
Conversely, with increasing lattice temperature, hot carrier relaxation rates
increase due to enhanced Shockley-Read Hall and surface recombination.
Time-resolved spectroscopy reveals a fourfold increase in the rate of
Shockley-Read-Hall recombination from 6 ns at 10 K to 1.5 ns at 150 K. The
findings suggest that minimizing defect densities in the bulk and surfaces of
these NWs will be key to enhance hot carrier effects towards higher
temperatures.
