Abstract: The study concerns the issue of how the morphological characteristics and optical properties of morphologically branched InGaN nanostructures grown on the Si(111) surface by molecular-beam epitaxy depend on the substrate temperature. It is shown that, as the substrate temperature is elevated, the height of InGaN nanocolumns formed at the initial stage of growth increases. In addition, an increase in the growth temperature of InGaN nanostructures yields an increase in the intensity of the photoluminescence spectra of such structures, and the dependences of the integrated photoluminescence intensity on the excitation power density are linear. These facts suggest that the structures offer promise for optical applications, specifically, for the creation of white light-emitting diodes on the basis of a unified material.