TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The device structure comprises at least one LED.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The step of forming the first III-nitride semiconductor material over the surface of the substrate comprises forming aluminum nitride over the surface of the substrate. The step of forming aluminum nitride over the surface of the substrate comprises forming a layer of aluminum nitride directly on the surface of the substrate. The method further comprises: selecting the substrate to comprise a sapphire substrate; forming at least one metal halide precursor by thermally decomposing at least one source gases, where the at least one source gas is gallium trichloride, indium trichloride or aluminum trichloride; forming at least one metal halide precursor by decomposing at least one of gallium trichloride, indium trichloride and aluminum trichloride and forming at least one of gallium chloride, indium chloride and aluminum chloride; exposing the substrate to a purge gas to remove at least one of excess group III element precursor and excess group V element precursor from the surface of the substrate; doping the second group III-nitride semiconductor material by mixing a dopant gas with the metal halide precursor; forming at least one active layer on or over the second group III-nitride semiconductor material; and faulting at least one device structure on or over the second group III-nitride semiconductor material. The step of forming the second group III-nitride semiconductor material over the first III-nitride semiconductor material comprises forming at least one of gallium nitride, indium gallium nitride, aluminum gallium nitride or indium aluminum gallium nitride over the first III-nitride semiconductor material, preferably forming layer of gallium nitride directly on the layer of aluminum nitride. The step of forming the layer of gallium nitride further comprises thermally decomposing a source gas comprising gallium trichloride to form a metal halide precursor comprising gallium chloride. The step of forming at least one of gallium nitride, indium gallium nitride, aluminum gallium nitride or indium aluminum gallium nitride further comprises thermally decomposing at least one source gases comprising gallium trichloride, indium trichloride or aluminum trichloride and forming at least one metal halide precursor comprising gallium chloride, indium chloride or aluminum chloride. The step of providing at least one metal halide precursor comprises forming at least a portion of the metal halide precursor by reacting a chlorinated species with liquid gallium. Preferred Components: The metal halide precursor comprises gallium chloride. The chlorinated species comprises at least one of hydrogen chloride and chlorine. EXAMPLE - No suitable example given.