Rapid thermal processing of Cu-rich (InGa)2Se3/CuSe bilayer precursors with an inset NaF layer

► Cu(InGa)Se2 can form using a bilayer (InGa)2Se3/CuSe precursor within 2-5 min. ► A thin NaF layer was inserted at the interface of (InGa)2Se3/CuSe precursors. ► MoSe2 thickness depends on the thickness of the NaF layer and the reaction time. ► Na doping resulted in increased (112) preferred orientation of the Cu(InGa)Se2.