셀레늄 과잉 전구체를 활용한 비셀렌화 스퍼터링 CIGS 박막 특성 연구

Abstract

In recent years, the usage of electric energy has been continuously increasing, and fossil fuel power generation and nuclear power generation are mainly used to obtain electric energy. However, fossil fuel power generation has problems such as depletion of resources, air pollution, price increase, greenhouse effect, etc., and nuclear power generation is problematic in safety such as radiation leakage. Therefore, research on new and renewable energy has attracted attention, and a lot of researches on this have been going on. Recently, a novel two-step precursor selenization method was proposed to improve the manufacturing process of CIGS thin film, which is a promising candidate for next generation thin film solar cell. In the two step precursor selenization process, the non-environmental problems of the selenization process as well as the risks of expensive manufacturing equipment and selenium gas were raised. In order to solve this problem, this thesis carried out to fabricate a CIGS thin film by a heat treatment process with non-selenization process. However, the composition-control problem of CIGS compound remains because of the inherent volatility of selenium caused by the low sublimation temperature leading to degradation of crystallinity. In this thesis, selenium composition ratio of the sputtered CIGS precursors was varied at some excessive composition ratios. Rapid thermal annealing process was used to control the composition ratio of the selenium-excess CIGS precursors and to improve crystallinity of them. The non-selenization process of the rapid thermal annealing was an effective method to improve the crystallinity of CIGS thin films. The chalcopyrite phases were observed with the selenium-excess precursors after the non-selenization process by controlling the selenium-volatility. The proper band gap and controllable resistivity can be obtained by this novel method.|In recent years, the usage of electric energy has been continuously increasing, and fossil fuel power generation and nuclear power generation are mainly used to obtain electric energy. However, fossil fuel power generation has problems such as depletion of resources, air pollution, price increase, greenhouse effect, etc., and nuclear power generation is problematic in safety such as radiation leakage. Therefore, research on new and renewable energy has attracted attention, and a lot of researches on this have been going on. Recently, a novel two-step precursor selenization method was proposed to improve the manufacturing process of CIGS thin film, which is a promising candidate for next generation thin film solar cell. In the two step precursor selenization process, the non-environmental problems of the selenization process as well as the risks of expensive manufacturing equipment and selenium gas were raised. In order to solve this problem, this thesis carried out to fabricate a CIGS thin film by a heat treatment process with non-selenization process. However, the composition-control problem of CIGS compound remains because of the inherent volatility of selenium caused by the low sublimation temperature leading to degradation of crystallinity. In this thesis, selenium composition ratio of the sputtered CIGS precursors was varied at some excessive composition ratios. Rapid thermal annealing process was used to control the composition ratio of the selenium-excess CIGS precursors and to improve crystallinity of them. The non-selenization process of the rapid thermal annealing was an effective method to improve the crystallinity of CIGS thin films. The chalcopyrite phases were observed with the selenium-excess precursors after the non-selenization process by controlling the selenium-volatility. The proper band gap and controllable resistivity can be obtained by this novel method.