A uniform, incoherent, uncorrelated beam of light can exert control over the morphology and growth direction of an evolving, inorganic semiconductor deposit in three-dimensional space at the nanoscale. No laser source, photomask nor structured light field is necessary nor utilized. Such evolution is similar to natural phototropism exhibited by many photosynthetic plants, including palm trees and sunflowers, wherein the physical extension of the biological system proceeds preferentially towards the time-averaged position of the sun while being influenced by competition from neighboring organisms. In analogy, during inorganic phototropic growth, the shape and growth direction of the deposited structures with respect to the substrate can be defined by controlling the angle of incidence of the light; mass is spontaneously added most preferentially to the localized regions capturing the maximal light flux. Optical coupling between neighboring features can result in further complexity and the emergent growth of highly ordered and complex film morphologies. Computer simulations of light absorption in deposits generated by inorganic phototropic growth, based on modeling of the fundamental interfacial light-material interactions, indicates that this growth process does in fact proceed in a manner reminiscent of the natural process of phototropism.