Effects of InGaN quantum disk thickness on the optical properties of GaN nanowires

•Effects of InGaN quantum disk thickness on optical properties of nanowires is investigated.•Nanostructures were grown by plasma assisted molecular beam epitaxy.•The emission of InGaN/GaN nanowires was examined using spectroscopic measurements.•Structural properties of InGaN/GaN Qdisk-in-NW heterostructures is also reported.•The variation of peak emission wavelength, spectral lineshape, width, and peak intensity with the change of Qdisk thickness was analyzed.