Preparation of CuInS2 Thin Film Solar Cells by Non-Vacuum Processes

• Main Authors: Chau-Le Wang, 王朝樂
• Other Authors: Yih-Min Yeh
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/68844461005597933104

碩士 === 吳鳳科技大學 === 光機電暨材料研究所 === 99 === Since the thin film solar cell is a future mainstream tendency, we used a non-vacuum method to manufacture solar cells incorporating a CuInS2 thin film. In contrast to traditional fabrication processes, the wet process with fast deposition can reduce the cost and have a high yield rate of producing solar cells. This experiment utilized a non-vacuum coating way of electrochemistry and CBD to grow the absorption layer of CuInS2 and the buffer layer of ZnS in the CIS solar cell. To analyze the film, X-ray diffractometry (XRD) was used to examine the crystalline structure and scanning electron microscope (SEM) was applied to measure the surface morphology. Furthermore, an energy dispersive spectrometer (EDS) was used to evaluate the film thickness and investigate the chemical composition. The results show that the electrodeposition method could grow the CuIn thin film with the (200) preferred orientation. In the experiment, the higher pH value of the plating solution could cause the thin film surface smoother, the crystallization pellet tinier, and the current density higher. Therefore, stress within the thin film might increase and fissure could be produced, especially for the current density higher than 1.5mA‧cm-2. In order to reduce the fissure of the thin film, we put saccharine in the solution. The addition of the saccharine could reduce the membrane stress with the CuIn film, mitigate the surface crack, and decrease the rich copper phase mixture . In the process of using the vulcanization treatment on CuInS2 thin film, we discovered that the Cu/In ratio reduced along with the temperature increase. At 600℃the ratio of Cu, In, and S was close to the standard chemistry measurement ratio of 1:1:2. However, the difference way of temperature elevation in vulcanization treatment had the influence on the thin film surface appearance. Growing the CuInS2 thin film by the first stage elevation of temperature had the worse the superficial compactness and the roughest surface. Using the second stage elevation of temperature caused the CuInS2 thin film with its pellet distribution more compact and hence more even surface. Furthermore, after the vulcanization treatment of CuInS2 thin film, rich mixed copper might appear on CuS. The study successfully used the electrochemistry way of etching for environmental protection to replace the traditional poisonous cyanide resolver. In summary, the non-vacuum way of the CIS thin film solar cell fabrication shows great potential to reduce the cost and improve the film quality for future applications.