Localization engineering of AlGaN nanowires: The issue of the inhomogeneity of III-nitride alloys is closely related to the potential of these materials for light emitting devices in a wide energy window. In two-dimensional layers, alloy composition fluctuations have been often correlated to structural defects. However, nitride nanowires provide an option to study these properties unbiased by the presence of extended defects. The results reported by Pierret et al. (pp. 868–873) suggest that kinetical effects are governing the growth mechanism of AlxGa1–xN nanowires with high Al content, leading to the formation of nanometric composition fluctuations. It is concluded that the carrier localization effects observed in these nanowires can be partly controlled by the growth parameters, leading to a wide range of localization potential values, opening the way to localization engineering and to enhanced room-temperature light emission in the UV range.