CdS Thin Films As Buffer Layer In Cigs Solar Cells Synthesized By Chemical Bath Deposition

Currently, as fossil energy exhausting and pollution problems, people force to seek alternative regeneration new energy. And the PV industry is becoming the strategic economic development of all countries in new industries. At the same time, Copper Indium Gallium Selenium thin film solar cells(CIGS) is also gradually in the industrialization. However, there are many obstacles that how to further improve the efficiency of the cells and ensure repeatability when large-scale industrialization. CIGS solar cells involves many film materials'preparation, which process is complex. Each layer materials for the preparation will have influence on the battery performance. In our this paper, we research the process and growth mechanism of CdS film deposited by Chemical Bath Deposition (CBD) as the buffer layer material.As deposition of CdS films by CBD, it mainly relates to the two film growth mechanisms, ion-by-ion and cluster-by-cluster. Different growth mechanism affects the properties of the fabricated film. The change of conditions (such as temperature, PH value, reactant concentration, composition of the solution and the deposition time) generates a lot of influence on the growth rate of films, crystal structure and surface morphology, optical properties. Because the influence of the concentration of reactants and pH value in the literature has so many reports, we emphatically chose deposition temperature and time to research the properties of film.CdS thin films were got by Chemical-bath-deposited at 60oC,70oC,80oC,90oC. Through analysis of planar and cross-section SEM, X-ray diffraction XRD, optical transmittance and bandgap value analysis, we explain film growth mechanism. Independent of the deposited-temperature, the growth was mainly controlled by the ion-by-ion growth mechanism in the beginning of the film deposition, and then the cluster-by-cluster mechanism came to be dominant.In addition, we also made some preliminary exploration in synthesising Copper zinc tin sulfur thin film (CZTS) by non-vacuum chemical method. Prepare the metal precursor using sol-gel method,and then sulfurizing.