NOVELTY - A copper/indium/gallium/selenium (CIGS) nanoparticles fabricating method involves milling materials using a first milling mediator and a first milling solvent in a milling machine. The obtained individual milled materials are mixed using a homogenizing solvent in a homogenizing machine. The obtained mixed homogenate is milled using a second milling mediator, a second milling solvent and a dispersant in a milling machine. The obtained primary milled materials are milled using a third milling mediator, a third milling solvent and the dispersant in a milling machine.    USE - Method for fabricating copper/indium/gallium/selenium (CIGS) nanoparticles that are utilized for producing an absorption layer of CIGS solar cell.    ADVANTAGE - The method enables fabricating copper/indium/gallium/selenium (CIGS) nanoparticles in an economical manner with less consumption of energy and without using a high precision apparatus. The method enables increasing the photoelectric conversion efficiency and high light absorbance of the CIGS solar cell.    DETAILED DESCRIPTION - A copper/indium/gallium/selenium (CIGS) nanoparticles fabricating method involves milling materials using a first milling mediator and a first milling solvent in a milling machine to produce individual milled materials, where the materials-being-milled comprise particles including copper, indium, gallium, and/or selenium, and compounds including copper selenide, indium selenide and gallium selenide, and a particle size of the individual milled materials is 500-600 nm. The individual milled materials are mixed using a homogenizing solvent comprising a binder and a surfactant in a homogenizing machine to produce a mixed homogenate. The mixed homogenate is milled using a second milling mediator, a second milling solvent and a dispersant in a milling machine to produce primary milled materials with particle size of 100-200 nm. The primary milled materials are milled using a third milling mediator, a third milling solvent and the dispersant in a milling machine to produce advanced milled materials with particle size of less than 50 nm, where the advanced milled materials are CIGS nanoparticles.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow chart illustrating a method for fabricating copper/indium/gallium/selenium nanoparticles.