A method of making nanostructures using a self-assembled monolayer of organic spheres is disclosed. The nanostructures include bowl-shaped structures and patterned elongated nanostructures. A bowl-shaped nanostructure with a nanorod grown from a conductive substrate through the bowl-shaped nanostructure may be configured as a field emitter or a vertical field effect transistor. A method of separating nanoparticles of a desired size employs an array of bowl-shaped structures.