Physical properties of CdS thin films deposited on activated substrates by using CBD technique M.L. Albor Aguilera1*, J.M. Flores Marquez1, M.A. González Trujillo2, G.L. Rueda Morales1 1 2 ESFM-IPN, Depto. Física, U.P.A.L.M., Zacatenco, México D.F. 07738, México. ESCOM – IPN, Formación Básica, U.P.A.L.M., Zacatenco, México D.F., 07738, México. *e-mail: [email protected] Abstract CdS thin films were deposited on substrates (SnO2:F) treated with HCl. CdS growth was influenced by the HCl activation becoming a surface free of holes and caverns without empty spaces among the grains, and with a uniform grain size distribution. The CdS particle size was reduced with HCl treatment. We obtained bi-layers of CdS with microand nano-metric particle size, which would help solve the problems of coating on the substrate. The CdS bi-layers obtained showed a higher quality growth and uniform morphology with thickness of 120 nm. All samples presented optical transmittance around of 85 – 90 %. CdS films have to fulfill some important characteristics to be used for solar cells application.