Abstract

ESTEVEZ, Josefa et al. Growth, structural, thermal, optical and electrical properties of CuIn₅S₈. Rev. Téc. Ing. Univ. Zulia [online]. 2009, vol.32, n.1, pp.60-67. ISSN 0254-0770.

In the present work the compound CuIn₅S₈ is obtained by direct fusion of the estoichiometric mixture of the constituent chemical elements. The data of the X-ray powder diffraction, indexed with the program TREOR 90, show a single-phase crystal with cubic spinel structure, space group Fd3m and unit cell parameter of 10,69 Å. Differential Thermal Analysis (DTA) measurements show that this crystal melts congruently around 1084ºC. Transmittance measurements were used to obtain the absorption coefficient a. From this last one two energy gaps E_g were found at room temperature, one direct and another indirect, with 1.41 and 1,25 eV, respectively. The reflectivity of this compound is reported for the first time and is used to confirm the energy gaps values obtained from transmittance measurements. The study of the electrical properties shows that the conductivity of the CuIn₅S₈ is n-type. Two activation energies were estimated from the Arrhenius plots of the resistivity and the carrier concentration, 56 meV and 0.16 eV, respectively.

Keywords : Ordered vacancies semiconductors; crystalline structure; phase transitions; energy gap; resistivity.