OPTICAL AND MORPHOLOGICAL PROPERTIES OF CdS NANOPARTICLES THIN FILMS DEPOSITED BY CBD PROCESS

摘要

CdS nanoparticles thin films have been fabricated using the chemical bath deposition (CBD) process; CdCl2.2,5H2O, thiourea [SC(NH2)2] and ammonium chloride [NH4Cl] were used as reagents. Special emphasis was placed on the study of the influence of the substrate and thiourea/CdCl2 ratio on the optical and morphological properties of the films; for that, samples deposited on glass, CuInSe2(CIS) and SnO2 substrates were characterized through Visible spectroscopy and AFM (atomic force microscopy) measurements. Through a parameter study it was found that CdS nanoparticles thin films with good substrate coverage and high transmittances (≈80 %) can be achieved by varying the molar concentration of thiourea between 0.5 and 1M and keeping the CdCl2 concentration in 0.1M. nanoparticles CdS thin films with these characteristics are desirable for using them as buffer layers in solar cells. The best parameter set found for the preparation of CdS nanoparticles thin films by the CBD method is the following: [CdCl2]= 0.1M, [thiourea]= 0.75 M, [NH4Cl2]= 0.2M, pH=10.2, Tsol=80°C.