p-Type electrical conduction and wide optical band gap in Mg-doped CuAlS2

A series of air-stable Mg-doped CuAlS2 powder samples and ceramic pellets with large band gaps over 3.0 eV have been prepared; their optical and electrical properties have been thoroughly investigated. Mg doping is effective in promoting the p-type conductivity of CuAlS2 with nominal sacrifice of the optical band gap. Conductivity as high as 41.7 S cm−1 is achieved at a doping level of 6 mol.%, which is much higher than that of most reported p-type transparent conductors.