Producción de películas delgadas de CdS$_{x}$ Te$_{1 - x }$ con estructura cúbica para $0 \le x \le 1$

Abstract

The CdS/CdTe heterostructure has great potential for the production of photovoltaic systems with more efficiency. One of the limitations to increase the efficiency is the difference in the crystal structure of CdTe and CdS that are cubic and hexagonal. Additionally, the presence of a region with gradual composition in the interfaz CdS/CdTe limits the uniformity of the interfacial electric field necessary to have a efficient separation of charge. To have a better knowledge of CdSTe alloy and eventually apport results that increase the actual efficiency we have grown thin films of CdS$_{x}$Te$_{1 - x}$ on glass substrate using the close spaced vapor transport combined with free evaporation technique (CSVT-FE) using the coevaporation of CdTe and CdS. The incorporation of the S was controlled by means of the CdS source temperature. The samples were characterized using X- ray diffraction, energy dispersive X ray spectroscopy and optical transmission. It was found that the samples have a cubic structure, for $0 \le x \le 1$, with their lattice parameter following the approach of virtual crystal. The forbidden band gap has a similar behavior to the one reported in the literature without showing changes due to the cubic structure for the whole range of compositions.