NOVELTY - Making (M1) a dopant based core/shell single-crystalline, one dimensional manganese doped cadmium and zinc sulfide (CdS:Mn/ZnS) nanowire involves: adding mixture of cadmium acetate, thiourea and ethylenediamine to reaction chamber; adding a dopant source to chamber; allowing reaction of mixture and dopant; adding mixed aqueous solution of zinc acetate dehydrate, thiourea and water; then allowing reaction of solution with and mixture; and collecting yellow precipitate that is washed, dried and analyzed to be a one-dimensional, doped CdS:Mn/ZnS core/shell nanowire.    USE - For synthesizing dopant based core/shell single-crystalline, one dimensional manganese doped cadmium and zinc sulfide (CdS:Mn/ZnS) nanowire (claimed) useful as spintronics material, and in a broad array of applications (such as materials for high-performance wave guide application, solar cell absorber material, room temperature yellow light emitting material, single nanowire based laser, thin-film nanowire transistor, light emitting displays (LED), non-linear optical materials and photonic circuit elements).    ADVANTAGE - The method produces CdS:Mn/ZnS nanowire having overall diameter of less than or equal to 10 (preferably 5-8) nm, length of 100-1000 nm and an overall length to diameter ratio of 150. The room temperature photoluminescence spectra of the core/shell nanowire obtained by the method exhibits strong yellow emission band at 585 nm wavelength along with a weak green emission peak at 514 nm wavelength. The method is simple, versatile and useful in a large scale production process to synthesize thin ultra-long CdS:Mn/ZnS core/shell nanowires (CSNWs) with and without dopants. The method provides a simple two-step solvothermal route for the fabrication or synthesis of thin single-crystal CdS:Mn/ZnS CSNWs; provides a fabrication or synthesis protocol for the large scale production of high quality, single crystalline, uniform structure core shell nanowires (CSNWs); provides a simple, cost-effective fabrication or synthesis method for CSNWs with high reproducibility; and also provides a fabrication or synthesis protocol for CSNWs with relatively low synthesis temperature (preferably 160 degrees C).    DETAILED DESCRIPTION - Synthesizing (M1) a dopant based core/shell single-crystalline, one dimensional manganese doped cadmium and zinc sulfide (CdS:Mn/ZnS) nanowire involves: selecting a reaction chamber; mixing cadmium acetate and thiourea in 1:3 molar ratio with ethylenediamine solvent to form mixture I; adding the mixture of cadmium acetate, thiourea and ethylenediamine (mixture I) to the reaction chamber; adding a dopant source to the reaction chamber; closing the reaction chamber for a first time and placing the chamber in a preheated oven; allowing the reaction of cadmium acetate, thiourea, ethylenediamine (mixture I) and dopant to continue for six hours to facilitate the solvothermal growth of cadmium sulfide nanorods and nanowires; removing the reaction chamber from the preheated oven after six hours and adding a mixed aqueous solution (mixture II) consisting of zinc acetate dehydrate, thiourea and water; closing the reaction chamber a second time and placing the chamber in a preheated oven; allowing the reaction of mixture I, dopant and mixture II to continue for an additional 4 hours to facilitate the growth of a doped cadmium sulfide core with a zinc sulfide outer shell; removing the reaction chamber from the preheated oven for a second time and allowing the reactor to cool; and collecting a yellow precipitate that is washed, dried and analyzed to be a one-dimensional, doped cadmium sulfide/zinc sulfide (CdS:Mn/ZnS) core/shell nanowire. An INDEPENDENT CLAIM is included for a thin dopant based core/shell single-crystalline, one dimensional nanowire (N1) comprising a doped cadmium sulfide core in a nanowire; and a zinc sulfide outer shell layered onto the doped cadmium sulfide core, where an overall diameter of the nanowire is less than or equal to 10 nm; and an overall length to diameter ratio is up to 150.