Resumen de Optical and structural properties of CdS:Pb^(2+) nanocrystals
R. Gutiérrez Pérez, O. Portillo Moreno, M. Chávez Portillo, H. Juárez, M. Pacio, L.A. Chaltel Lima, M. Zamora, M. Lazcano, C. Rubio, G. Hernández Téllez
The goal of this work is to study the effects of doping on structural, morphological and optical properties of CdS thin fims as a function of Pb^(2+) concentration. Thus, nanoparticles are synthesized by chemical bath and a thickness decrease of "approx." 575-200 nm range was observed. In Fourier-transform infrared spectroscopy, all the samples showed a sharp stretching mode observed at "approx." 1384 cm^(-1) corresponding to the vibration mode of CO_(3)^(-2). X-ray diffraction studies show that the size of crystallites is in the "approx." 33-12 nm range. The peaks belonging to primary phase are identified at the 2"theta" = 26.5º and 2"theta" = 26.00º, corresponding to CdS and PbS respectively. Thus, a shift in maximum intensity peak from 2"theta" = 26.4º to 28.2º is observed. Likewise peaks at 2"theta" = 13.57º, 15.91º correspond to lead perchlorate thiourea. The optical, absorption, and transmission properties of the fims were determined by UV-vis spectrophotometry, optical energy gap was found to range from 2.1 to 2.4 eV. Raman spectroscopy on doped films showed a shifting of these modes that can be attributed to strain, stress effects, defects, phonon confinement, and variation in phonon relaxation with rain size.
