Electrical properties and structural changes of thermally co-evaporated CuInSe films

Thermal co-evaporation technique (from two sources - Cu wire and In30Se70 i ngots) was used to prepare CuInSe thin films. Controlling the evaporation r ates from the sources was helpful to get films having different Cu/In conte nt. The temperature dependence of the electrical conductivity was investiga ted in the temperature range 80K less than or equal to T less than or equal to 435 K. The density of localized states at the Fermi level and the activ ation energy for conduction are decreased on increasing the film (Cu/ In) c ontent. The activation energy for conduction of the Cu20In20Se60 film decre ases on increasing the annealing temperature. Tetragonal CuInSe2 and hexago nal Cu2Se crystalline phases resulting from heat treatment have been identi fied using X-ray diffractometry and transmission electron microscope. (C) 2 001 Elsevier Science B.V. All rights reserved.