Cationic and anionic modification of CdS thin films by surface chemical treatment

Alejandro Baray-Calderón, Próspero Acevedo-Peña, Omar A. Castelo-González, Claudia Martínez-Alonso, Mérida Sotelo-Lerma, M.C. Arenas-Arrocena, Hailin Hu

Producción científica: Contribución a una revistaArtículorevisión exhaustiva

9 Citas (Scopus)

Resumen

Structural and physical properties of thin solid films can be modified by surface treatment. In this work, chemical bath deposited CdS thin films were treated both by a mercury chloride solution and by a saturated H 2 S gas. The effect of these treatments on electrical properties is clearly observed. Hg 2+ doped CdS films show the highest dark and photo-conductivities, whereas the sulfurized CdS films become photo-insensitive. In Hg 2+ doped CdS samples, new crystalline Hg 3 S 2 Cl 2 and Hg 2 (ClO 4 ) 2 4H 2 O phases are found, and particle size reduction is observed at the surface. Both optical and electrochemical Mott-Schottky (M–S) analysis suggest an intraband level in the electronic structure of Hg 2+ modified CdS. Sulfurized CdS films, on the other hand, keep unchanged their crystalline and morphological structure, as well as optical properties. Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and M–S analysis indicate an increase of sulfur concentration at the surface of sulfurized CdS thin films, leading to a more stoichiometric CdS compound, which used to have lower conductivity. It demonstrates that ion exchange process or cationic substitution is effective for structural and physical property modification, whereas a gaseous saturation method or anionic modification results in a notable surface energy alteration in thin solid CdS films.

Idioma originalIndefinido/desconocido
Páginas (desde-hasta)676-683
Número de páginas8
PublicaciónApplied Surface Science
Volumen475
DOI
EstadoPublicada - may. 2019

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