A method includes defining, on a surface of a material, a plurality of discrete portions of a surface as surface elements having at least one of a laterally-varying size, a laterally-varying shape, and a laterally-varying spacing. A plurality of portions of the material beneath the surface elements are doped with a single quantity of dopant material per element area. The dopant material within the material beneath the surface elements expands to provide a lateral gradient of dopant material in the material beneath the surface elements.