| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 97 === The ternary chalcopyrite CuInSe2-like absorber is a promising material for the fabrication of thin-film solar cells due to its high optical absorption coefficient (~105 cm-1), adjustable band gap, and potential for long-term stability [1]. CIS films can be n- or p-type depending on its chemical composition, defect structures and preparation conditions. The highest efficiencies of 19.9% [2] and 16.9% [3] for thin-film Cu(In,Ga)Se2 (CIGS) and Cu(In,Al)Se2 (CIAS) solar cells have been realized by the multi-source elemental co-evaporation process, respectively. Like other thin films, they can also be fabricated by a variety of processes such as selenization [4], ink printing [5], electrodeposition [6], and so on. Film morphology could significantly impact on down stream solar cell processing and efficiency.
This thesis studied film morphology of CI(A)S thin film formed by selenizatoin of various ratio of Cu to In(Al) precursors prepared by sputtering. The composition effects on morphologies of (In,Al)-rich, Cu-rich, and near stoichiometric CI(A)S thin films were studied using selenization of stacked elements precursors. The results show that Cu-rich and near-stoichiometric CI(A)S films had larger grains and smoother surface than (In,Al)-rich film, indicating that In composition (or thickness) can influence on film crystallization as well as morphology. No obvious differences were found for film selenization in graphite box or aluminum box. CI(A)S (112) was the preferred orientation for all studied samples.
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