Electronic structure and doping of p-type transparent conducting oxides

Transparent conducting oxides (TCOs) are a group of materials that are widely used in solar cells and other optoelectronic devices. Recently, Cu-containing p-type TCOs such as M^IICu₂O₂ (M^II = Mg, Ca, Sr, Ba) and CuM^IIIO₂ (M^III=Al, Ga, In) have been proposed. Using first-principles band structure methods, we have systematically studied the electronic and optical properties of these p-type transparent oxides. For M^IICu₂O₂, we predict that adding a small amount of Ca into SrCu₂O₂ can increase the transparency and conductivity. For CuM^IIIO₂, we explained the doping and band gap anomalies in this system and proposed a new approach to search for bipolar dopable wide-gap materials.