QUANTUM CONFINEMENT EFFECTS ON CD1-XNIXTE SPUTTERED FILMS

By using the r.f. sputtering technique CdNiTe nanostructured layers we re prepared onto glass substrates. The nanoparticles in the films appe ar to have spherical shape with broad grain-size distribution. The mea sured average diameters were 35, 30, and 26 nm corresponding to 5, 10, and 15 nickel percent atomic content in the film, respectively. Energ y dispersion spectroscopy indicates that Ni enters into the CdTe latti ce in Cd sites. The structure of the nanostructured layers was zincble nde cubic that resembles the bulk CdTe semiconductor. Particle-size ef fects on optical absorption spectra were observed. As the Ni content i ncreases, the grain-size diameter diminishes, and the band-gap energy (E-g) increases. E-g shifts have been found higher than the predicted values from the strong and weak quantum confinement models. Disagreeme nt was explained by considering extra E-g shifts as an effect of the l attice shrinkage originated from the replacement of Cd2+ by Ni2+ with smaller ionic radius, into the CdTe lattice. (C) 1998 Elsevier Science S.A.