Crystal structure and band-edge transitions of ReS2-xSex layered compounds

Single crystals of the ReS2-xSex solid solution series have been grown by t he chemical vapor transport method using Br-2 as a transport agent. From an alyzing the X-ray patterns, the series crystals are determined to be single -phase and crystallized in the triclinic layered structure. The lattice par ameters of the compound series are evaluated and discussed. The optical abs orption edge was measured on basal-plane at room temperature. The results r eveal that ReS2-xSex are indirect semiconductors and their energy gaps are determined. The band gap energy varies smoothly with the Se composition x, indicating that the nature of band edges are similar for the end members Re S2 and ReSe2, and the compounds of intermediate compositions. (C) 1999 Else vier Science Ltd. All rights reserved.