Eur. Phys. J. Special Topics 153, 299-302 (2008)
https://doi.org/10.1140/epjst/e2008-00450-4

Characterization of chemical bath deposited CdS thin films doped with methylene blue and Er³⁺

¹ Departamento de Física, Centro de Investigación y de Estudios Avanzados-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, Del. G.A. Madero, México 07300, D.F., Mexico
² Facultad de Ciencias Físico-Matemáticas, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Río Verde, Col. San Manuel, Ciudad Universitaria, Puebla 72570, Puebla, Mexico
³ Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Río Verde, Col. San Manuel, Ciudad Universitaria, Puebla 72570, Puebla, Mexico

Corresponding author: stomas@fis.cinvestav.mx

Abstract

The optical, electrical, and structural properties of CdS thin films grown by chemical bath deposition and simultaneously doped with methylene blue (MB) and Er³⁺ were studied. Doping was achieved by adding a constant volume of an MB aqueous solution to the chemical bath while the relative volume (V_R) of the Er aqueous solution varied within the range 0–10% of the total growing solution. X-ray diffractograms displayed the zincblende crystalline structure for all the CdS samples, with a remarked preferred orientation along the (111) direction. The interplanar distance among the (111) planes decreased for low doping leves of Er³⁺, while for high doping concentrations such distance increased to saturation. Measurements on the carriers density indicated that the CdS thin films doped with Er³⁺ at 6% V_R presented the maximum value. In addition, the band gap energy (Eg) resulted higher for CdS:MB films with low Er³⁺ doping levels than for undoped films; however, Eg decreased until stabilization for increasing Er³⁺ concentrations.