Enhancement of hot carrier effects in core-shell InGaAs nanowires by Auger heating

Hot carrier solar cells are a category of third-generation photovoltaic devices focused on enhancing solar technology efficiency beyond the theoretical limits of single-junction devices. A crucial aspect of designing effective hot carrier solar cells is minimizing the rates of hot carrier thermalization within the solar cell absorbers. Nanowires (NWs) present promising opportunities for hot carrier solar cells due to their one-dimensional structure and favorable density-of-states characteristics. This study examines the hot carrier effects in core-shell InGaAs/InAlAs nanowires with diameters ranging from 110 nm to 200 nm. The findings from photoluminescence spectroscopy indicate a significant relationship between hot carrier effects and nanowire diameter. Specifically, as the diameter decreases from 200 nm to 160 nm, the hot carrier effects become more pronounced. However, further reduction in diameter, particularly below 160 nm, results in diminished hot carrier effects. The observed increase in hot carrier effects as the diameter decreases (between 160 nm and 200 nm) is attributed to the combined influences of phonon bottleneck and Auger heating mechanisms. Conversely, in the thinner nanowires, an increase in microstructural disorder contributes to higher rates of hot carrier thermalization, leading to reduced hot carrier effects. These results are consistent with existing theoretical models and previous experimental studies, including those employing time-resolved photoluminescence spectroscopy and high-resolution transmission electron microscopy.