Strengthening for sc-Si Solar Cells by Surface Modification With Nanowires

Bending strength of single-crystalline silicon (sc-Si) substrates enhanced by forming silicon nanowires (SiNWs) on the surfaces has been investigated for the application of sc-Si solar cells. As operated under the three-point-bending test, the 40-mm-long, 20-mm-wide, and 0.61-mm-thick sc-Si substrates show a high bending strength of 1.02 ± 0.11 GPa and maintain bulk properties. By this strengthening method, a hand-bent 6-in 0.23-mm-thick sc-Si solar cell shows the displacement of 35 mm and the curvature radius of 75 mm. Moreover, the bending strengths of strengthening sc-Si substrates for the SiNW depths of 1, 2, and 4 μm are 2.1, 4.3, and 6 times larger than that of pristine sc-Si substrates (i.e., 0.17 ± 0.01 GPa), respectively.