An Investigation of Optical Absorption of Pulsed Nd:YAG Laser Texturing on Silicon Solar Cells Surfaces Before and After Post Treatment

In this paper, results of optical absorption of Pulsed Nd:YAG laser texturing on silicon solar cells surfaces, before and after post treatment were investigated. Silicon is known as a semiconductor which absorbs light poorly. This is because silicon material has indirect energy bandgap about 1.12 eV at room temperature which limits the efficiency of solar cells. Due to the material price, the thin silicon wafer solar cells are used to fabricate solar cells. Thin silicon solar cells is inexpensive and can perform better by improved the technique on fabrication of solar cells. One of the technique to improve solar cells efficiency for thin silicon wafer is a light trapping. Thin silicon wafer come with disadvantages which is cannot absorb longer wavelength. Therefore, to improve light trapping on thin silicon solar cells, a good textured must be created on the top of the silicon wafer surface in order to prolong the light path refractive and reflective inside the solar cells. This paper shown Pulsed Nd:YAG laser is used for making parallel pattern and grid pattern as a textured on silicon wafer top surfaces. After laser texturing is completed, the samples were then immersed in KOH solution. KOH solution is used to removed the unwanted particles and clean the silicon surfaces. An expected result of this investigation is that the optical absorption for both after post treatment Grid pattern and Parallel pattern exhibit high absorption, compared to the sample of Grid pattern and Parallel pattern non-post treatment which have low absorptions. The higher value of absorption for laser texturing on silicon wafer is start from 380 nm until 880 nm. The absorption decrease a little bit from 880 nm until 1050 nm. Interestingly, the silicon wafer with laser textured still have absorption for infrared light from 1050 nm until 1200 nm. This results means, laser texturing with post treatment can improved light absorption of thin silicon wafer which is trap more photons thus will resulting high efficiency.