Large-Scale Micro- and Nano-Patterns of Cu(In, Ga)Se₂ Thin Film Solar Cells by Mold-Assisted Chemical Etching Process
Yi-Chung Wang1*, Hsiang-Ying Cheng1, Yu-Ting Yen1, Tsung-Ta Wu1,2, Cheng-Hung Hsu1, Hung-Wei Tsai1, Chang-Hong Shen2, Jia-Min Shieh2, Yu-Lun Chueh1
1Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
2National Nano Device Laboratories, Hsinchu, Taiwan
* presenting author:Yi-Chung Wang,
A reactive mold-assisted chemical etching (MACE) process through an easy-to-make agarose stamp soaked in bromine methanol etchant to rapidly imprint larger area micro- and nano- arrays on CIGS substrates was demonstrated. Interestingly, by using the agarose stamp during the MACE process with and without additive containing oil and triton, CIGS microdome and microhole arrays can be formed on the CIGS substrate. Detailed formation mechanisms of microstructures and the chemical composition variation after etching process were investigated. In addition, various micro-and nano-structures were also demonstrated by this universal approach. The microstructure arrays integrated into standard CIGS solar cells with thinner thickness can still achieve an efficiency of 11.22 %, yielding an enhanced efficiency ~18 % compared with that of their planar counterpart due to an excellent absorption behavior confirmed by the simulation results, which opens up a promising way for the realization of high-efficiency micro- or nanostructured thin-film solar cells. Finally, the complete dissolution of agarose stamp into the hot water demonstrates an environmental-friendly method by the mold-assisted chemical etching process through an easy-to-make agarose stamp.

Keywords: Cu(In, Ga)Se2, Agarose, Micro-and nano-structures, Mold-assisted chemical etching