Abstracts Book - IMRC 2018

• SF2-P031
SYNTHESIS AND CHARACTERIZATION OF Co-DOPED CdS
NANOFILMS DEPOSITED BY CHEMICAL-BATH DEPOSITION
Joel Díaz Reyes 1 , Jorge Indalecio Contreras Rascon 2 , Miguel Galvan Arellano 3 , Jose Saul Arias
Ceron 3 , Roberto Saul Castillo 4
1 Instituto Politécnico Nacional - IPN, Centro de Investigación en Biotecnologia Aplicada, Mexico.
2 Universidad del Valle de Puebla, División de Ingenierías, Mexico. 3 Centro de Investigación y de
Estudios Avanzados del IPN - CINVESTAV, Depto. de Ingenieria Electrica, SEES, Mexico.
4 Universidad Politécnica de Pachuca, , Mexico.
Co-doped CdS nanofilms are prepared using a chemical bath deposition (CBD)
growth technique at the reservoir temperature of 70±2°C. The Co molar
concentration ranged of 0.0£x£0.2, which was determined by Energy-dispersive
X-ray spectroscopy (EDS). The X-ray diffraction results show that the films are of
CoS-CdS composites with individual CdS and CoS planes. The CdS shows zinc
blende (ZB) crystalline phase that was determined by X-ray diffraction (XRD)
analysis and it was confirmed by Raman spectroscopy. The average grain size of
the CdS films was ranged 19.91 to 24.28 nm that was determined by Debye-
Scherrer equation ZB (111) direction and it was confirmed by high-resolution
transmission electron microscopy (HRTEM). Raman scattering shows that the
lattice dynamics is characteristic of bimodal behaviour and the multipeaks
adjust of the first optical longitudinal mode for the Co-doped CdS denotes the
Raman shift of the characteristic peak at 305 cm -1 of the CdS crystals is
associated with the cobalt ions incorporation. The nanofilms exhibit two direct
band gaps, ~2.44 eV attributed to CdS, which increases lightly as the cobalt molar
fraction is increased and another is about 3.05 eV associated with nanocrystals
size. The photoluminescence at room temperature of the CdS presents three
bands well resolved in 2.99, 2.40 and 1.91 eV. The first band is associated with
the radiative band-band transition due to the quantum confinement and the
other two are due to structural defects. For the Co-doped CdS nanolayers, the
photoluminescence increases, which indicates a high passivation of the
nanocrystals. The increase in band gap with increase in cobalt concentration
suggests inter-metallic compound of CoS (E g =1.6 eV) with CdS (E g =2.44 eV).
Keywords: CdS, CBD, Cobalt
Presenting authors email: joel_diaz_reyes@hotmail.com