1 Enhanced performance of solar cells with anti- reflection layer fabrication by nano-imprint lithography Solar Energy Materials & Solar Cells ■ ( ■ ■ ■ ■ ) ■ ■ ■ – ■ ■ ■ Kang-Soo Han, Ju-Hyeon Shin, Woo-Young Yoon, Heon Lee Advisor ： Cheng-Hsin Chuang Advisee ﹕ Hung-Liang Chien Institute of Mechanical Engineering Date ﹕ 2011/03/14

2 Outline  Introduction  Imprinting process Ni master mold was fabricated by laser interference lithography PVC mold was fabricated by hot-embossing with Ni master mold  Conclusion  Acknowledgements

Introduction 3 PET with pattern PET w/o pattern

4 Imprinting Process

5 Ni master mold was fabricated by laser interference lithography silicon (2) Exposure silicon photoresist (1) Printing silicon Ni (4) Electroforming silicon (3) Develoment Ni (5) Ni mold SEM image of Ni master mold

Imprinting Process 6 Ni master mold was fabricated by laser interference lithography Hexane solution Ni (6) SAM Coating

Imprinting Process 7 PVC mold was fabricated by hot-embossing with Ni master mold Ni PVC (1) Ni Pressing (2) Hot-embossing (3) De-molding Ni (4) PVC mold SEM image of duplicated PVC mold

Imprinting Process 8 PVC mold was fabricated by hot-embossing with Ni master mold Silane based (6) SAM Coating PVC Anode Cathode Silicon Plasma Ar + O2 SiO2 (5) SiO2 RF-Sputtering

9 Imprinting Process AFM images of imprinted pattern and its section analysis

Conclusion 10 Additional layer with moth-eye pattern on the surface of GaAs cell that the total convension efficiency was increased. (1) Reflection of the GaAs solar cell with/without the moth-eye structure measured as a function of the wavelength (2) I-V characteristics of the GaAs solar cell with/without the moth-eye pattern

Acknowledgements 11 [1] Kang-Soo Han, Ju-Hyeon Shin, Woo-Young Yoon, Heon Lee, Enhanced performance of solar cells with anti- reflection layer fabricated by nano-imprint lithography, Sol. Energy mater. Sol. Cells (2010) [2] Tien-Li Chang, Kuei-Yuan Chang, Ta-Hsin Chou, Chieh Su, Han-Ping Yang, Shao-Wei Luo, Hybrid-polymer nanostructures forming an anti-reflection film using two-beam interference and ultraviolet nanoimprint lithography, Microelectronic Eng. 86 (2009) [3] Eun-Ju Honga, Kyeong-Jae Byeona, Hyoungwon Parka, Jaeyeon Hwanga, Heon Leea,Kyungwoo Choib, Gun Young Jung, Fabrication of moth-eye structure on p-GaN layer of GaN-based LEDs for improvement of light extraction, Materials Science and Engineering B 163 (2009) 170–173 [4] J.Y. Chen, K.W. Sun, Enhancement of the light conversion efficiency of silicon solar cells by using nanoimprint anti-reflection layer, Solar Energy Materials & Solar Cells 94 (2010) 629–633

12 Thanks for your attention