Optical and structural study of CdS capped with ethylenglycol

Many articles have been reporting about the influence of surface in the optical, electrical and structural properties of nanoparticles (1-3). These properties are controlled during the growth process or after of been obtained the nanoparticles. The control consists to cap the surface of the nanoparticles. This process allows separating the nanoparticles, reducing or eliminating the surface traps and also could influence the size and distribution of nanoparticles. Our presentation makes a study about the influence of organic molecules in the structural and optical characteristics of nanoparticles. Syntheses of CdS nanoparticles were obtained using colloidal methods. We investigate the influence of the inclusion of organic molecules and temperature during the growth to try to improve its properties. The samples were characterized by UV-VIS absorption, X-ray, Raman and Photoluminescence (PL). From the measurements we obtained that the samples have a good crystalline quality. The X-ray measurements show that the size and structure of the samples depend on molar fraction of the organic molecules used during growth. The PL spectra of the samples show that the organic molecules decrease efficiently the number of surface traps. Further increasing the organic molecules concentration does not decrease any further the number of traps, however, the number of surface traps is always smaller than in uncapped nanoparticles.