Lattice constants and band-gap variations of the pentenary semiconductor system Cu1−yAgyInS2(1−x)Se2x

Abstract

Much interest has been expressed in the ternary IB‐III‐VI₂ group semiconductors for use in electro‐optical devices such as solar cells. Subsets of these, AgInS₂, AgInSe₂, CuInS₂, and CuInSe₂, have been combined to form the pentenary alloy system Cu_1−yAg_yInS_2(1−x)Se_2x. With such an alloy the band gap may be varied while keeping the lattice constant fixed. Samples were prepared by reacting stoichiometric powder mixtures at about 900 °C. X‐ray diffractometry tests suggest the alloys maintained complete solid solubility throughout the system in a chalcopyrite‐type crystal structure. From cathodoluminescence studies on pressed bars of these powders the band‐gap energies were estimated at 300 °K. These tests suggest that the alloys are all direct‐band‐gap semiconductors.