Preparation of Cu2ZnSnS4 Target for RF Sputtering Deposition of Cu2ZnSnS4 Solar Cell Materials

• Main Authors: JIANG, GUAN-TING, 江冠霆
• Other Authors: YEH, MIN-YEN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/47441565661055115009

碩士 === 國立高雄海洋科技大學 === 微電子工程研究所 === 105 === In recent years, global warming and the depletion of fossil fuels have made green energy more and more important. Solar energy is one of the important green energy sources. It is clean and inexhaustible making it being a promising alternative energy source. In this study, Cu2ZnSnS4 (CZTS) was chosen as the theme. It is a kind of P-type direct energy gap semiconductor. Zinc and tin are abundant in the Earth making CZTS a low-cost material. Sulfur is non-toxic and high absorption coefficient. CZTS has an energy gap of 1.4~1.6 eV which is suitable for use as solar cell absorbent layers with high efficiency of solar conversion. In this study, CZTS target powder was prepared by sol-gel method. The CZTS powder was sulfurized to enhance its quality. A high quality CZTS sputtering target was prepared by pressing the CZTS powder into bulk. Sputtering method has following advantages: (1) strong adhesion, (2) suitable for high melting point substances, (3) large area deposition, and (4) reactive deposition. Higher quality CZTS solar cell thin films can be prepared by RF sputtering by exactly controlling RF power and pressure. Therefore, this study combined with the advantages of sol-gel for synthesizing CZTS powder and RF plasma sputtering method for depositing CZTS solar cell film. The properties of CZTS such as crystal structure, surface morphology, element composition, energy gap, electrical analysis, etc., were analyzed by X-ray diffract-meter (XRD), Raman spectra, field emission gun scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), α-step, UV-visible spectroscopy (N & K) and Hall measurement. In this study, the CZTS powder with Kesterite structures was confirmed by XRD analysis. As CZTS films were deposited at 35 W and 20 mtorr, a significant Raman shift of CZTS was confirmed at 336 cm-1. Its resistance coefficient is 7.69×10-2 ohm-cm, and absorption coefficient is over than 104 cm-1. Its energy gap is ~1.34 eV which makes it suitable for using as solar cell absorption layers.