Influence of Auger heating and Shockley-Read-Hall recombination on hot-carrier dynamics in InGaAs nanowires

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 the 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 dependences of hot carrier effects on the degree of confinement of photogenerated 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 one to estimate the Fröhlich 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.