Characterization of ZnS Thin Films Grown Using Chemical Bath Deposition with Three Different Complexing Agents.

Cadmium sulfide buffer layer was replaced with zinc sulfide thin film owing to toxicity. ZnS thin films were fabricated using chemical bath deposition. The inhibition of Zn(OH)2 and high uniformity are important factors for the deposition of ZnS. The characteristics of ZnS thin films were analyzed by adding ethylenediamine tetra-acetate acid (EDTA) and hexamethylene tetramine (HMTA). The morphological characteristics of the ZnS buffer layer are closely related to the use of a complexing agent which controls the concentration of Zn2+ ions and Zn(OH)2 in the deposition process. The addition of the complexing agent EDTA accelerated the cluster-cluster method but it exhibited lower uniformity and greater cracking phenomenon. HMTA can be effectively applied to increase the amount of Zn2+ ions forming ZnS. It can be easily found as Zn2 HMTA at high temperatures. The results of the experiment with the addition of HMTA revealed that the surface of the thin film did not change with the increase in the concentration of HMTA, but the thickness of the thin film increased gradually. HMTA promoted the ion-ion method to grow the thin film uniformly, but the speed was slow. Moreover, an experiment by using mixed EDTA and HMTA as the complexing agent was performed. The best ZnS thin film with a transmittance of 83% and a denser surface was prepared using HMTA complexing agent.

Influence of Post-Heat Treatment of ZnO:Al Transparent Electrode for Copper Indium Gallium Selenide Thin Film Solar Cell.

Copper indium gallium selenide (CIGS) thin film solar cells have been regarded as a candidate for energy conversion devices owing to their high absorption coefficient, high temperature stability, and low cost. ZnO:Al thin film is commonly used in CIGS solar cells as a window layer. In this study, ZnO:Al films were deposited on glass under various post-heat temperature using RF sputtering to observe the characteristics of ZnO:Al films such as Hall mobility, carrier concentration, and resistivity; subsequently, the ZnO:Al films were applied to a CIGS solar cell as a window. CIGS solar cells fabricated with various ZnO:Al films were analyzed in order to investigate their influence. The test results showed that the improvement of ZnO:Al characteristics affects Jsc and Voc in the solar cell through reduced recombination and increase of optical property.