Eur. Phys. J. B 26, 401-406 (2002)
https://doi.org/10.1140/epjb/e20020106

Analysis of optical spectra of CdS and CdSe films deposited on a sapphire substrate by laser ablation technique

¹ Dipartimento Interateneo di Fisica, Università di Bari, Via Amendola 173, 70126 Bari, Italy
² Istituto Nazionale Fisica della Materia, Unità di Bari, Via Amendola 173, 70126 Bari, Italy
³ Facoltà di Medicina e Chirurgia, Università di Foggia, Viale L. Pinto, 71100 Foggia, Italy

Corresponding author: ^a vito.capozzi@ba.infn.it

Received: 21 June 2001
Revised: 18 November 2001
Published online: 15 April 2002

Abstract

CdSe and CdS films, deposited on a sapphire substrate by means of pulsed laser ablation technique, have been investigated by means of reflectivity and photoluminescence measurements in order to study the effect of such a transparent substrate on the optical properties of the deposited epilayers. The reflectivity spectra at low temperature have been studied by means of an analytical model which permits one to obtain the energies of the excitonic resonances. The photoluminescence spectra show that our CdSe and CdS films present excitonic emission at low temperature, differently from the same films deposited on quartz. The temperature dependence of the excitonic energy has been analysed by taking into account the contribution of both the thermal expansion and electron-phonon interaction. The exciton linewidth has been analysed according to well known phenomenological models.