NOVELTY - The method involves growing III-nitride heterostructure at a growth temperature chosen to prevent layer disordering. Heterostructure layers are doped with an impurity during growth. The heterostructure is post-growth annealed at an annealing temperature, time and carrier gas pressure that induces disorder of heterostructure layer interfaces. A dielectric layer is deposited on a portion of the surface of the doped heterostructure prior to the post-growth annealing.    USE - Method for impurity-induced layer disordering in III-nitride materials to create a device. Uses include but are not limited to optical waveguide, light-emitting diode, photodetector, solar cell, modulator, laser and amplifier.    ADVANTAGE - The method enables post-growth annealing the heterostructure at the annealing temperature, time and carrier gas pressure that induces disorder of the heterostructure layer interfaces such that the heterostructure can be selectively disordered when the post-growth annealing conditions promote layer disordering in the portions of the heterostructure without the dielectric overlayer and the portions of the heterostructure covered by the dielectric layer are prevented from layer disordering.    DETAILED DESCRIPTION - The III-nitride heterostructure comprises aluminum gallium nitride/aluminum nitride layer, gallium nitride/aluminum nitride layer, gallium nitride/aluminum gallium nitride layer, indium gallium nitride/gallium nitride layer, indium gallium nitride/aluminum nitride layer, indium gallium nitride/aluminum gallium nitride layer, aluminum indium nitride/gallium nitride layer, aluminum indium nitride/aluminum nitride layer and aluminum indium nitride/indium gallium nitride layer. The dielectric layer comprises silicon mononitride, silicon oxy-nitride and silicon dioxide. The carrier gas comprises nitrogen, ammonia, hydrogen and helium.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view a device comprising a p-n junction.    Quantum well (QW)