GROWTH AND SPECTRAL DEPENDENCE OF THE ABSORPTION-COEFFICIENT OF CUGATE2 THIN-FILMS

The optical properties of CucaTe(2) polycrystalline thin films deposit ed by vacuum evaporation as a function of growth conditions are discus sed in terms of the crystal structure. Absorption coefficients are det ermined from reflection and transmission measurements in the photon en ergy range 1 to 3 eV. The optical absorption data show four characteri stic energy gaps at 1.22, 1.28, 1.42, and 2.20 eV which correspond to fundamental, band splitting (crystal field and spin-orbit), and copper 3d level transitions, respectively. The frequency dependences of opti cal constants n, k, e', and e'' are also given.