Excitonic luminescence of CdSxSe1−x films deposited by laser ablation on Si substrate

The structural and optical properties of CdSxSe1−x alloy films, deposited on Si(111)-oriented substrates by the laser ablation technique, have been investigated. The films grow highly oriented in the hexagonal phase and the lattice constant c of the ternary alloy follows Vegardʹs rule. The exciton line recombination is well resolved in the PL spectra of each film alloy from 10 up to 300 K. The temperature dependence of the excitonic energy indicates that both acoustic and optical phonons contribute to the thermal shrinkage of the band gap: in particular, the acoustic phonon contribution is larger in ternary compounds than in the binary ones.