J.S. Arias-Cerón

Physical properties of CdTe:Cu films grown at low temperature by pulsed laser deposition

CdTe:Cu films were grown by pulsed laser deposition on Corning glass slides at a substrate temperature of 300 °C. The thin films were grown using CdTe and Cu2Te powders, varying the Cu2Te concentration from 3 to 10 wt. %. The structural, compositional, optical, and electrical properties were analyzed as a function of the nominal copper concentration. X-ray diffraction shows that films have CdTe cubic phase. The compositional analysis indicates that CdTe:Cu films grown with lower Cu content have Te excess, on the other hand, films with higher Cu content have Te deficiencies. The electrical measurements showed that CdTe:Cu films grown with low Cu content present lowest resistivity.

Study of the structure, optical properties, surface morphology and topology of ZnO thin films grown by sol–gel on silicon substrates

Polycrystalline visible light photoluminescent zinc oxide (ZnO) thin films have been grown on silicon substrates by the dip immersion sol?gel technique at low sintering temperature. The optical properties of the films were analyzed by UV?vis spectroscopy. The structural properties were measured with x-ray diffraction. The results show that the films are polycrystalline and have hexagonal wurtzite structure. The estimated band gap of the samples by UV?vis absorption spectroscopy is in good agreement with the value measured by UV?vis reflectance spectroscopy and is near 3.2 eV. The surface topography was observed with atomic force microscopy. The morphology of the samples was analyzed by scanning electron microscopy. Energy dispersive x-ray spectroscopy was used to make chemical composition measurements, the results indicate that the sample is stoichiometric. The photoluminescence (PL) spectroscopy shows a strong band in the blue?green region of the spectrum, which makes these films interesting to optoelectronic applications.

Stoichiometric 6H-SiC thin films deposited at low substrate temperature by laser ablation

Silicon carbide thin films were grown by laser ablation on silicon substrates at different deposition temperatures using SiC powders as target material. The structural, morphological, compositional, and optical properties were studied as a function of the deposition temperature. The 6H-SiC crystalline phase was observed by Raman spectroscopy, x-ray diffraction, and transmission electron diffraction without the presence of any other polytype. In the room temperature photoluminescence spectra, a broad band was observed in the visible region which suggests that these films can have applications on silicon based optoelectronics.