| 초록 |
Multicrystalline silicon is an attractive substrate for solar cells because it is a much cheaper material than monocrystalline silicon. Unfortunately, its electrical properties are worse than those of monocrystalline silicon. In particular, the limitation for the use of mc-silicon is the inability to effectively texture the front surface. In this work, a HF-free laser texturing process was proposed and the effect of post-laser cleaning on the properties of the solar cell was investigated. Laser texturing of wafers was performed with a Nd-YAG picosecond laser with a wavelength of 1064nm and anisotropic alkaline etching was performed. The alkaline cleaning effectively removed the globules of laser-induced defects from the textured surfaces and, the cleaning (etching) provided pseudo-pyramidal structures on the mc-silicon wafer surfaces.. However, when the texturing process is accompanied with alkaline cleaning, it was necessary to find the optimum etching time. The time should be long enough for removing the laser-induced damages and obtaining rough surfaces. In addition, the time should not be so long to prevent the formation of high steps at the grain borders. |
