TECHNOLOGY FOCUS - ELECTRONICS - Preferred Component: A solar cell has a substrate, a barium silicide layer containing barium and silicon provided on the substrate, an impurity doped barium silicide layer containing impurity such as arsenic, antimony, bismuth and/or nitrogen, barium and silicon provided on the barium silicide layer, an upper electrode provided on the impurity doped barium silicide layer and a lower electrode provided on the substrate. The solar cell further has a metal silicide layer containing metal chosen from group (9-10) in periodic table and silicon between the barium silicide layer and substrate. The barium silicide layer is an epitaxially layer or highly oriented layer. Preferred Arrangement: The lower electrode is provided on the surface of the metal silicide layer.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: A barium silicide layer (2) and an impurity doped barium silicide layer (3) contain alkali-earth metal such as strontium, calcium and/or magnesium. A surface of a substrate (1) contains silicon. The barium is introduced into silicon surface of the substrate, and barium and silicon are reacted. Preferred Property: The semiconductor material is n-type semiconductor material. Preferred Process: The alkali-earth metal such as strontium, calcium and/or magnesium are reacted to obtain semiconductor material. The silicon and barium are reacted to form barium silicide layer on the substrate. The impurity such as barium, silicon, arsenic, antimony, bismuth and/or nitrogen is reacted with the surface of the barium silicide layer to form an impurity doped barium silicide layer. A lower electrode (5) is formed on the substrate. An upper electrode (6) is formed on the surface of the impurity doped barium silicide layer to obtain solar cell. The barium silicide layer is formed by epitaxy method. The silicon and metal of group (9-10) of periodic table are reacted to form metal silicide layer on the substrate. A silicon ultra-thin layer is formed on the surface of the metal silicide layer.