CIS계 태양전지 응용을 위한 전기증착법을 이용한 CIS흡수층과 ZnO 박막 형성 기술 연구 = CuInSe2 and ZnO film formed using electrodeposition for the application of CuInSe2 Solar Cell

다국어 초록 (Multilingual Abstract)

Thin-film solar cell technology is a promising alternative to silicon solar cell technology. CuInSe2 (CIS) based solar cells has become one of the leaders in this field. In recent years, chalcopyrite CIS polycrystalline thin film has gained interest due to its high absorption coefficient, the possibility of band gap engineering, and long-term opto-electronic stability. Theses CIS thin film advantage result in the potential for its use as an absorber material in solar cell application. For instance, a conversion efficiency of over 20.3% has been achieved in CIS based thin film solar cells, This implies that these cells are comparable in performance to existing crystalline Si solar cells. Until now, various deposition techniques have been proposed to prepare CIS absorber layers such as co-evaporation, radio frequency (RF) sputtering, molecular beam epitaxy (MBE), chemical bath deposition, spray pyrolysis, and electrodeposition. Among them, electrodeposition has received considerable attention due to advantages such as low cost equipment, a minimum waste of components, and scalability of large area thin film deposition with a high growth rate. In other words, compared to other deposition techniques, low-cost and large-scale production of CIS based solar cells can be achieved using electrodeposition. In this study, stoichiometric CIS absorber layers were formed using co-electrodeposition coupled with selenization. We investigated the influence of the supporting electrolyte, addition agent, and deposition voltages on the structural and chemical properties of Cu-In alloys. The increases in deposition voltage, the ratio of In to Cu in the Cu-In alloy increased, and surface morphology improved. Finally, based on an optimized co-electrodeposition process, the selenization of Cu-In alloys using the evaporation of the Se element was employed to form high quality CuInSe2 absorber layers. Also, ZnO film formed using electrodeposition by the application of CIS Solar Cell. We investigated the effect of bath temperature and electrode potential on the microstructural and chemical properties of ZnO films formed on Mo-coated soda-lime glass substrates using electrodeposition. The increase in deposition temperature resulted in an enhancement of the crystallinity and growth rate of ZnO film. The change of the mole ratio of Zn to O was insignificant when bath temperature increased up to 40°C, above which the ZnO film with the same concentration of Zn and O atoms was formed. Similarly, under electrodeposition condition with the bath temperature of 50°C, the growth rate of ZnO film increased with increasing electrode potential. When electrode potential exceeded -1.2 V, hydrogen-bubble formation steadily occurred near growing surface, which could be responsible for the degradation of the surface morphology of ZnO film. The precursors , selenization, ZnO film were characterized by scanning electron microscopy (SEM), electron probe micro analysis (EPMA), X-ray diffraction (XRD) and scanning transmission electron microscopy-energy dispersive X-ray (STEM-EDX).

목차 (Table of Contents)

• Abstract
• 그림 목록
• 표 목록
• 제 1장 서론 1
• 제 2장 이론적 배경
• 2.1 태양전지 5
• 2.1.1 태양전지의 원리
• 2.1.2 태양전지의 분류
• 2.2. CIS계 박막형 태양전지 16
• 2.3 전기증착(Electrodeposition) 23
• 2.3.1 전기증착의 특징
• 2.3.2 전기증착의 원리
• 2.3.2 전기증착의 방법
• 제 3장 실험
• 3.1 Mo 증착 31
• 3.2 동시전기증착 35
• 3.3 셀렌화열처리 38
• 3.4 ZnO전기증착 40
• 제 4장 결과 및 논의
• 4.1 공정조건에 따른 Mo 박막 특성 변화 41
• 4.2 증착전압과 전해질 그리고 첨가제에 따른 전구체 특성변화 45
• 4.3 셀렌화 열처리 후의 CIS 흡수층 특성 59
• 4.4 증착온도와 전압에 따른 ZnO의 특성 변화 63
• 제 5장 결론 72
• 참고문헌 73
• 발표 논문 및 학회 발표