NOVELTY - The method comprises supporting a non sodium alkaline glass substrate in an atmospheric pressure, dissociating a solid-state selenium source by a plasma head (200) to deposit a selenium thin-film on the substrate, supplying sodium on the substrate by introducing sodium fluoride into the plasma head, heating the substrate at a temperature of less than 500 degrees C when the selenium thin-film is deposited on the substrate, and extracting the air from opposite sides of the substrate when the selenium thin-film is deposited on the substrate.    USE - The method is useful for depositing a selenium thin-film on a substrate of thin-film solar cells.    ADVANTAGE - The method is capable of energy-efficiently and easily depositing the selenium thin-film on the substrate of the thin-film solar cells thus enhancing quality and productivity of the solar cells and reducing the production cost of the solar cells.    DETAILED DESCRIPTION - The method comprises supporting a non sodium alkaline glass substrate in an atmospheric pressure, dissociating a solid-state selenium source by a plasma head (200) to deposit a selenium thin-film on the substrate, supplying sodium on the substrate by introducing sodium fluoride into the plasma head, heating the substrate at a temperature of less than 500 degrees C when the selenium thin-film is deposited on the substrate, and extracting the air from opposite sides of the substrate when the selenium thin-film is deposited on the substrate. The plasma head and the substrate move relative to each other by moving the plasma head when the selenium thin-film is deposited on the substrate. INDEPENDENT CLAIMS are included for:    (1) an apparatus for the deposition of a selenium thin-film; and    (2) a plasma head.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of an apparatus for depositing a selenium thin-film on a substrate of thin-film solar cells.    Main body (10)    Support table (100)    Plasma head (200)    Transmission mechanism. (300)