Addition of Zn element into CdS improves the short circuit current density and open circuit voltage to increase the efficiency of hetero-junction based solar cells such as CdTe and CIGS, decreasing the absorption losses of the window materials in p-n junction devices and the lattice mismatch.
Over the past three decades, there have been a number of reports on the deposition and properties of Cd1-xZnxS ternary compound with a various range of Zn concentration (low Zn content, midst content and overall Zn content), using different methods like chemical bath deposition, spray pyrolysis, SILAR, vacuum evaporation, MOCVD, RF sputtering, vapor zinc chloride treatment, etc.
Ki Tong Hun, a student at the Faculty of Electronics, has deposited Cd1-xZnxS thin films (0<x<1) by the CBD method and investigated the influence of Zn content on the structural, morphological, optical and electrical properties of films by using XRD, SEM, UV-VIS spectroscopy and other analysis instruments.
The analysis results can be summarized as follows;
XRD studies revealed that the crystal phase of Cd1-xZnxS thin film changed from the hexagonal to hexagonal/cubic mixed phase at lower Zn contents, and then transformed to cubic ZnS phase as Zn content further increased.
Through the SEM measurements, he could observe certain-sized granules formed by the agglutination of Cd and Zn compounds around the nucleus due to the absorption of Cd2+ and Zn2+ ions with initial increase of Zn concentration. On the other hand, for the Zn content greater than 0.6, Cd1-xZnxS particle size decreased and the mixture phase in thin film became stable.
For further details, please refer to his paper “Investigation on the influence of Zn content on the structural, optical, morphological and electrical properties of ternary compound Cd1-xZnxS window layer for CdTe solar cell” in “Functional Materials Letters” (SCI).
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