The present invention relates to a metallic layer adjacent to a semiconducting layer comprising a substantially covalent matrix material, the metallic layer comprising at least one first metal and at least one second metal, wherein a) the first metal is selected from the group consisting of Li, Na, K, Rb, Cs; and b) the second metal is selected from the group consisting of Zn, Hg, Cd, Te, electronic devices comprising such materials and process for preparing the same.