The influence of radial heterostructuring on carrier dynamics in gallium nitride nanowires

Ultrafast optical pump-probe spectroscopy is used to study the influence of aluminum nitride (AlN) and aluminum gallium nitride (AlGaN) shells on carrier dynamics in radially heterostructured GaN nanowires (NWs). Our experiments reveal longer carrier relaxation times and lower lasing thresholds in NWs passivated with a higher bandgap shell, which can be attributed to a reduction in surface defect state density. We observe that carrier relaxation times vary with the nitride shell material and thickness, likely due to strain from the lattice mismatch between the core and shell materials. Our results demonstrate that radial heterostructuring is a promising route to controlling carrier dynamics in III-nitride NWs.