Large Tolerance of Lasing Properties to Impurity Defects in GaAs(Sb)-AlGaAs Core-Shell Nanowire Lasers

GaAs-AlGaAs based nanowire (NW) lasers hold great potential for on-chip photonic applications, where lasing metrics have steadily improved over the years by optimizing resonator design and surface passivation methods. The factor that will ultimately limit the performance will depend on material properties, such as native- or impurity-induced point defects and their impact on non-radiative recombination. Here, the role of impurity-induced point defects on the lasing performance of low-threshold GaAs(Sb)-AlGaAs NW-lasers is evaluated, particularly by exploring Si-dopants and their associated vacancy complexes. Si-induced point defects and their self-compensating nature are identified using correlated atom probe tomography, resonant Raman scattering, and photoluminescence experiments. Under pulsed optical excitation the lasing threshold is remarkably low (<10 µJ cm⁻²) and insensitive to impurity defects over a wide range of Si doping densities, while excess doping (Si]>10¹⁹ cm⁻³) imposes increased threshold at low temperature. These characteristics coincide with increased Shockley-Read-Hall recombination, reflected by shorter carrier lifetimes, and reduced internal quantum efficiencies (IQE) . Remarkably, despite the lower IQE the presence of self-compensating Si-vacancy defects provides an improved temperature stability in lasing threshold with higher characteristic temperature and room-temperature lasing. These findings highlight an overall large tolerance of lasing metrics to impurity defects in GaAs-AlGaAs based NW-lasers.