Order and disorder in epitaxially grown CuInS2

This study investigates the ordering effects which occur on the cation subl attice of the CuInS2 compound. CuInS2 is grown on single-crystalline silico n substrates of (001) orientation. The ordered, sulfur-terminated surface S i(001)(1 x 1)-S constitutes well-defined starting conditions for the epitax ial growth process using molecular beams. The silicon surfaces and epitaxia l CuInS2, films are characterized in situ by means of Auger electron spectr oscopy and low-energy electron diffraction. X-Ray diffraction, and transmis sion electron microscopy are employed for an ex situ structural characteriz ation. We demonstrate the coexistence of CuAu-type ordering and disorder an d a complete absence of the equilibrium chalcopyrite order. CuInS2, with th e tetragonal CuAu structure is shown to grow exclusively in c-axis directio n. (C) 2001 Elsevier Science B.V. All rights reserved.