Copper indium gallium selenide
|Copper indium gallium selenide|
CIGS unit cell. Red = Cu, yellow = Se, blue = In/Ga
|Melting point||1070-990 °C(x=0–1)|
|Band gap||1.7–1.0 eV (x=0–1)|
|Crystal structure||tetragonal, Pearson symbol tI16 |
|Lattice constant||a = 0.56–0.58 nm (x=0–1), c = 1.10–1.15 nm (x=0–1)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
Copper indium gallium (di)selenide (CIGS) is a I-III-VI2 semiconductor material composed of copper, indium, gallium, and selenium. The material is a solid solution of copper indium selenide (often abbreviated "CIS") and copper gallium selenide. It has a chemical formula of CuInxGa(1-x)Se2 where the value of x can vary from 1 (pure copper indium selenide) to 0 (pure copper gallium selenide). CIGS is a tetrahedrally bonded semiconductor, with the chalcopyrite crystal structure, and a bandgap varying continuously with x from about 1.0 eV (for copper indium selenide) to about 1.7 eV (for copper gallium selenide).
Among many uses, CIGS is best known as an alternate solar cell material in thin-film solar cells. In this role, CIGS has the advantages of being able to be deposited on flexible substrate materials, producing highly flexible, lightweight solar panels. Improvements in efficiency have made CIGS a leader among alternative cell materials.
CIGS is a tetrahedrally bonded semiconductor, with the chalcopyrite crystal structure. Upon heating it transforms to the zincblende form and the transition temperature decreases from 1045 °C for x=0 to 805 °C for x=1.
- Tinoco, T.; Rincón, C.; Quintero, M.; Pérez, G. Sánchez (1991). "Phase Diagram and Optical Energy Gaps for CuInyGa1−ySe2 Alloys". Physica Status Solidi (a) 124 (2): 427. doi:10.1002/pssa.2211240206.
- "DOE Solar Energy Technologies Program Peer Review". U.S. department of energy 2009. Retrieved 10 February 2011.