Passivation of localized states in GaAs/GaNAs core/Shell nanowires by post-growth hydrogenation

Abstract

Due to its attractive electronic properties, the GaNAs alloy is considered a promising material for optoelectronic applications in the near-infrared spectral region. Unfortunately, nitrogen incorporation is also known to lead to material degradation due to the formation of non-radiative defects and strong band tailing effects caused by alloy disorder. In this study, we show that post-growth hydrogenation of GaNAs-based nanowires (NWs) can largely suppress these unwanted effects. First, we find that this treatment results in a more homogeneous electronic structure due to the passivation of nitrogen-related band tail states, without affecting the bandgap energy of the material. Additionally, hydrogenation reduces the density of quantum emitters that are spontaneously formed in dilute nitride NWs upon N incorporation. This leads to spectrally isolated emission lines from these emitters, which is important for creating high-purity single-photon sources. Finally, the treatment improves the overall optical quality of the material, giving an up to threefold increase in the intensity of band-to-band emission after hydrogenation. Our findings, therefore, highlight the potential of hydrogenation as a viable approach for improving material quality and tailoring the optoelectronic properties of GaNAs NWs without compromising their emission wavelength, paving the way for their integration into telecom-compatible photonic devices.