Promising transparency and p-type conductivity of Li, Na, K and Rb-doped CaS: A first-principles study

•We predict that CaS is a promising transparent p-type conducting material.•High transmittance and low absorptivity hold the optical transparency.•Li, Na, K and Rb substituting at Ca sites are efficient acceptors.•The defect compensation effects are negligible due to rather low solubility of hole-killers.•The predicted holes concentration can exceed 1017 cm−3 at 300 K.