Composition-dependent Defect Structure of Heteroepitaxial CuInS2 Films grown by Molecular Beam Epitaxy

Epitaxial CuInS₂/Si(111) films were prepared by molecular beam epitaxy in a composition range [In]/([Cu]+[In])=0.42–0.54. The about 100nm thick epilayers were characterized by double crystal x-ray diffraction. Whereas Cu-rich films with low defect density were obtained, the FWHM of In-rich films is increased by a factor 2–3.

Transmission electron microscopy reveals that In-rich films are characterized by enhanced stacking faulting and twin formation on (112) and (112̄) planes. Cu-rich films exhibit relatively few stacking faults and microtwins only on (112).