U.S. Department of Energy - Energy Efficiency and Renewable
Energy  SunShot Initiative  Copper Indium Gallium Diselenide
Graphic showing the five layers of a CIGS PV cell: glass (or
metal foil or plastics), Mo, CIGS, CdS, and transparent
conductive oxide.  CIGS photovoltaic cell structure. Image by
Alfred Hicks/NREL  DOE-sponsored research on copper indium
gallium diselenide [Cu(InxGa1-x)Se2], or CIGS, solar cells
focuses on developing better film qualities, and thus, higher
efficiencies. A list of current projects, summary of the
benefits, and discussion on the production and manufacturing of
this solar technology are below.   Since its initial
development, copper indium diselenide (CuInSe2) thin-film
technology has been considered promising for solar cells because
of its favorable electronic and optical properties. It was later
found that by substituting gallium (Ga) for indium (In), the
bandgap can be increased from about 1.04 electron-volts (eV) for
copper indium diselenide (CIS) films to about 1.68 eV f