Spectral diffusion and its influence on the emission linewidths of site-controlled GaN nanowire quantum dots

Abstract

Fourier transform spectroscopy is used to determine/control the degree of spectral diffusion in high-quality site-controlled GaN nanowire quantum dots. Detailed analysis, including the development of a statistical model and Monte Carlo simulations, provides evidence that the broadening is caused by photoinduced excitation of defects. Furthermore, performing the experiment under weak excitation allows for an estimate of the homogeneous linewidth to be made $(135\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{eV})$. The origins of this linewidth are discussed, and the existence of an alternate dephasing mechanism is inferred. A limit on the emission linewidth at zero excitation is also discussed.