Crystallographic, optical, and electronic properties of Cu(In,Ga)Se<sub>2</sub> and Cu-deficient phases, Cu(In,Ga)<sub>3</sub>Se<sub>5</sub> and Cu(In,Ga)<sub>5</sub>Se<sub>8</sub> in Cu<sub>2</sub>Se-(In,Ga)<sub>2</sub>Se<sub>3</sub> pseudo-binary System/2018 International Conference on Solid State Devices and Materials