Preparation and Optical Characterization of Nanostructures on Silicon Wafer and ZnO Films

• Main Authors: Ming-lun Wu, 吳明崙
• Other Authors: Ing-Chi Leu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/34962665205125316068

碩士 === 國立臺南大學 === 材料科學系碩士班 === 101 === Low conversion efficiency is still the main limiting factor for current solar cells. Most of the energy loss during solar cell operation is attributed to light reflection. To reduce the light reflection, we can change the path of light entering the solar-cell. In addition, to increase the energy conversion efficiency, light trapping is a key point to the cell structure. We can increase light trapping by a textured transparent conduction oxide (TCO) layer. Because the textured films can enhance the light trapping, the textured TCO films can get thinner compared with the thicker flat films. There are two parts in this study. First, we etched the pyramidal structure on silicon wafer to get the hierarchical structure by an electroless metal deposition-assisted etching method. We changed the Ag deposition time, etching temperature, HF concentration, H2O2 concentration and etching time, and discussed the influence of the different parameters on the structure and optical properties of the silicon wafer. Second, we used a sol-gel method to get the textured ZnO films. We changed sol-gel concentration, different preheat temperature, different heat treatment temperature, to discuss the influence of different parameter on the preparation of wrinkles films. Then we got high transmittance, high haze, low resistivity by coating FTO films on ZnO films. We showed the lowest reflectance about 1.7 % at wavelength 550 nm by moderating the H2O2 concentration during Si etching. By changing zinc oxide concentration, we showed the best result of about 72.2 % haze, 83 % transmittance and sheet resistance 44 Ω/□. ZnO wrinkles will be impressed by the doping of Al and their dimensions get flatter, resulting the ZnO films with a lower haze.