NOVELTY - The method comprises: providing a conductive substrate (400); depositing a first selenium film layer over the substrate; forming a first precursor solution (600) including a first material set such as metal salts and/or metal complexes, dissolved in a solvent; depositing the first solution on the first selenium film layer; forming a first intermediate film comprising metal precursors, formed from corresponding members of the first material set; and thermally annealing in an environment consisting of hydrogen, hydrogen selenide and/or selenium/hydrogen.    USE - The method is useful for forming a solution-processed metal and mixed-metal selenide semiconductor using a selenium film layer (claimed) for electronic and photovoltaic (PV) applications e.g. copper indium gallium selenide (CIGS) solar cell.    ADVANTAGE - The method is capable of providing both improved copper indium gallium selenide (CIGS) absorber layer morphology and interfacial contacts through additional selenium supply so as to minimize requirement of selenization towards the fabrication of the CIGS absorber layer.    DETAILED DESCRIPTION - The method comprises: providing a conductive substrate (400); depositing a first selenium film layer over the substrate; forming a first precursor solution (600) including a first material set such as metal salts and/or metal complexes, dissolved in a solvent; depositing the first solution on the first selenium film layer; forming a first intermediate film comprising metal precursors, formed from corresponding members of the first material set; thermally annealing in an environment consisting of hydrogen, hydrogen selenide and/or selenium/hydrogen; transforming the metal precursors in the first intermediate film; and forming a metal selenide-containing semiconductor. The conductive substrate is made of metals, metal alloys, metal oxides, and/or mixed metal oxides. The method further comprises: forming a second precursor solution (602) including a second material set selected from the first set, dissolved in a solvent, prior to thermal annealing; depositing the second solution on the first intermediate film; and forming a second intermediate film comprising metal precursors, formed from corresponding members of the second material set. The intermediate film forming step comprises forming a first proportion of the first intermediate film with a material including metal oxides and mixed metal oxides. The transforming step comprises transforming metal precursors in the first and second intermediate films. The method further includes forming a second selenide film layer over lying the first intermediate film, prior to thermally annealing; transforming some proportion of metal-containing materials in the conductive substrate, as a result of thermal annealing; and forming a metal selenide-containing layer in the conductive substrate underlying the metal selenide-containing semiconductor.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a process for forming a solution-processed metal and mixed-metal selenide semiconductor.    Conductive substrate (400)    Molybdenum film (402)    First precursor solution (600)    Second precursor solution (602)    Selenium film. (604)