STRUCTURAL AND ELECTRONIC TRANSPORT-PROPERTIES OF RESI2-DELTA SINGLE-CRYSTALS

We investigated some structural and transport properties of semiconducting ReSi2-delta. In the Literature this silicides is reported to crystallize in an orthorhombic structure and to be stoichiometric ReSi2. Our investigations clearly show that the stable composition is ReSi1.75 crystallizing in the space group P1. Transport measurements show thermally activated behavior at high temperatures with one (or two) energy gap E(g) = 0.16 (0.30 eV). We also report Hall-effect measurements on this material: we found that R(H) is positive between 30 and 660 K and at room temperature the Hall number n(H) = 1/eR(H) is equal to 3.7 X 10(18) cm(-3). The Hall mobility at room temperature is relatively high (mu(H) = 370 cm(2)/V s) for a single crystal. (C) 1995 American Institute of Physics.