• InAsN nanowires with up to 0.7% nitrogen incorporation exhibit a red-shifted photoluminescence due to conduction band splitting, confirming the formation of a polytypic hexagonal nitride solid solution.
• Surface passivation with an InP shell significantly reduces nonradiative recombination, enabling room-temperature photoluminescence emission from InAs-based nanowires.
• The polytypic structure of the nanowires, dominated by wurtzite phase with parasitic sphalerite islands, is directly reflected in the low-temperature photoluminescence spectra.
• Controlling the composition and morphology of InAs-based nanowires allows tuning their electronic structure, offering potential for tailored mid-IR detectors and sources.