NOVELTY - The method comprises establishing operation of a reaction chamber of a substrate (1010) at a first predetermined set of operating conditions, introducing a first source of sources into the reaction chamber in the absence of a second source of sources for a first predetermined period of time at a predetermined flow rate and/or predetermined pressure, establishing operation of the reaction chamber at a second predetermined set of operating conditions after the predetermined period of time is elapsed, and introducing the first and second sources of the sources into the reaction chamber.    USE - The method is useful for growing semiconductor nanowires without foreign metal catalyst, where the semiconductor nanowires are useful for solid state lights sources and full solar spectrum solar cells.    ADVANTAGE - The method is capable of efficiently and rapidly growing defect free semiconductor nanowires with high uniformity and quality, improved structural properties and reduced energy consumption and without requirement of foreign metal catalyst thus improving the efficiency of the solar spectrum solar cells.    DETAILED DESCRIPTION - The method comprises establishing operation of a reaction chamber of a substrate (1010) at a first predetermined set of operating conditions, introducing a first source of sources into the reaction chamber in the absence of a second source of sources for a first predetermined period of time at a predetermined flow rate and/or predetermined pressure, establishing operation of the reaction chamber at a second predetermined set of operating conditions after the predetermined period of time is elapsed, introducing the first and second sources of the sources into the reaction chamber in addition to the first source of the sources and the second source of the sources at a predetermined flow rate and/or a predetermined pressure, operating the reaction chamber at the second predetermined set of operating conditions for a second predetermined period of time. The first source of the sources provides a source of a group III element. The second source of the sources provides a source of nitrogen. The reaction chamber comprises controllable inlets for the first and second sources of the sources. The first predetermined set of operating conditions result in the formation of nanoscale droplets of the group III element on the surface of the substrate, and comprise establishing the reaction environment as nitrogen rich and/or establishing the substrate temperature of: 400-550 degrees C when the group III element is indium; 700-900 degrees C when the group III element is gallium; and 900-1200 degrees C when the group III element is aluminum. The growth of the semiconductor comprising the group III element and nitrogen within the reaction chamber is initiated without the presence of a foreign catalyst. The second predetermined set of operating conditions comprises establishing the reaction environment as nitrogen rich and/or the substrate temperature of: 500-800 degrees C when the sources relate to the ternary semiconductor indium gallium nitride; 500-1200 degrees C when the sources relate to the ternary semiconductor indium aluminum nitride; and 500-1200 degrees C when the sources relate to the quaternary semiconductor indium gallium aluminum nitride. The operation of the reaction chamber at the second predetermined set of operating conditions comprises performing a predetermined series of growth steps by a predetermined set of operating conditions for the reaction chamber, a predetermined time and a predetermined set of conditions for the sources. The resulting semiconductor growth comprises a nanowire, a quantum dot, a quantum well, a heterostructure, a p-i-n diode, and a quantum dot comprising nanoclusters characterized in group III element composition higher than the surrounding quantum dot. The semiconductor comprises the group III element is grown in the presence of silicon nitride formation on the silicon. The first source of the sources comprises the group III element and/or a precursor comprising the group III element and for providing the group III element in elemental form as the result of a reaction within the reaction chamber. The method further comprises initiating the growth of a wurtzite semiconductor onto a substrate, continuing the growth of the wurtzite semiconductor for a predetermined period of time, and growing a series of semiconductor materials in a predetermined sequence atop the wurtzite semiconductor. The initiation step is achieved through providing nanoscale droplets of a group III element constituent of the wurtzite semiconductor on the surface of the substrate and absent both a foreign catalyst and other constituent elements of the wurtzite semiconductor. The series of semiconductor materials comprise a quantum dot, a quantum well, a barrier (1030), a heterostructure, a p-doped semiconductor, an intrinsic semiconductor, a n-type semiconductor, quantum dot comprising nanoclusters characterized in a group III element composition higher than that of the surrounding quantum dot, and/or a graded semiconductor grading from a first composition to a second composition. An INDEPENDENT CLAIM is included for a device for growing semiconductor nanowires without foreign metal catalyst.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of nanowires light source employing nanowires featuring dot-within-a-dot-in-a-nanowire features for efficient optical sources.    Substrate (1010)    Buffer (1020)    Barrier (1030)    Large quantum dots (1040)    Small quantum dots (1045)    Capping layer (1050)    Electrode. (1060)