Formation of Ag(Ga, In)Se2 During Selenization of Ag-Ga/In Precursor

The substitution of Ag for Cu in Cu(Ga, In)Se2 has been shown to optimize the bandgap of the chalcopyrite while decreasing defect density and formation temperature. The synthesis of chalcopyrite via selenization of metal precursor films with a complete substitution of Ag for Cu was studied both in-situ during selenization using high temperature x-ray diffraction and ex-situ using electron microcopy. AgInSe2 formation at low temperatures was limited by the availability of Ag in the liquid phase resulting in the formation of Ag-deficient Ag-In-Se phases. Ga alloying into AgInSe2 at high temperature was limited by the stability of (Ga, In)2Se3.