Effect of precursor structure on Cu(InGa)Se2 formation by reactive annealing

Precursor structures of Mo/CuGa/In, Mo/In/CuGa, Mo/In/CuGa/In and Mo/CuGaIn were prepared on thin sodium-free glass by the sputtering of CuGa and In targets. In-situ phase evolution of precursors with temperature was investigated by a high-temperature X-ray diffraction system, which verified the existence and transformation of several intermetallics: Cu2In, Cu11In9, Cu3Ga, Cu7In3, Cu9Ga4 and Cu16In9 as well as elemental In. MoSe2 layers produced during selenization were detected by scanning electron microscope and X-ray diffraction, with their thicknesses varying by precursor structure. Adhesion strength of Cu(InGa)Se2 to each Mo layer was assessed by applying CdS chemical bath deposition process to each sample.