After deposition, by evaporation under vacuum, of Al/Cu/Te. multilayer
structures, annealing at 673 K or more for half an hour, under argon flow, allows CuAlTe2
films crystallised in the chalcopyrite structure to be obtained. The optical and electrical
properties are interpreted by introducing the influence of impurity foreign phases present in
the films. The optical properties are sensitive to the small Al2O3 domains randomly
distributed into the CuAlTe2 polycrystalline matrix. The optical band gap is slightly increased
(2.35 eV) by the presence of alumina. The conductivity measurements show that a short
circuit effect can be induced by a binary Cu$_{2-x}$Te degenerate phase present at the surface of
the films. This effect can be suppressed by KCN etching of the samples that allows the
superficial foreign phase to be dissolved.