The optical bandgap OSI-906 supplier of thin film after the irradiation was also calculated, as shown in Table 3. The optical bandgap decreases rapidly as the irradiation dose rises from 0 to 10 × 1014 ions/cm2. After that, as the irradiation dose rises from 10 × 1014 ions/cm2 to 50 × 1014 ions/cm2, it gradually levels off. Table 3 Optical bandgap after irradiation   Irradiation dose (1014 ions/cm2) 1 5 10 50 E g (eV) 1.64 1.52 1.46 1.42 As shown in Figure 6, ion irradiation

has distinct influence on the optical bandgap of the original film, but it may lead to a limitation as the irradiation dose increases. The optical bandgap exponential decays with the irradiation dose, and the fitting formula of the curve is . Previous research showed that the optical bandgap decreased as the grain size of silicon expanded

[16], which suggests that a possible AMN-107 datasheet recrystallization mechanism happened during the ion irradiation process. Figure 6 The negative exponential relation between the optical bandgap and the irradiation dose. Conclusions We prepared self-assembled monolayers of PS nanospheres and fabricated periodically aligned silicon nanopillar arrays by magnetic sputtering deposition. We improve the absorptance of thin film by changing the diameter of the silicon nanopillar. With the increase of the diameter of the nanopillar, optical bandgap decreases and absorptance increases. The influence of Xe ion irradiation on the optical bandgap was also investigated. The bandgap decreases with the increase of irradiation dose. It may be induced by the recrystallization during the irradiation and lead to the change in grain size, which is closely related to the bandgap of the film.

Authors’ information selleck All authors belong to the School of Materials Science and Engineering, Tsinghua University, People’s Republic of China. FY is a master candidate interested in amorphous silicon thin film. ZL is an associate professor whose research fields include thin film material and nuclear material. TZ is a master candidate interested in the fabrication of nanostructure. WM is an associate professor working on nanostructure characterization. ZZ is the school dean professor with research interest in nanostructures and SERS effect. Acknowledgements The authors are grateful to the financial support by the National Natural Science Foundation of China (under Grants 61176003 and 61076003). References 1. Carlson DE, Wronski CR: Amorphous silicon solar cell. Appl Phys Lett 1976,28(11):671.CrossRef 2. Green MA, Emery K, JQ-EZ-05 mouse Hishikawa Y, Warta W, Dunlop ED: Solar cell efficiency tables (version 39). Prog Photovolt Res Appl 2011, 20:12.CrossRef 3. Chopra KL, Paulson PD, Dutta V: Thin-film solar cells: an overview. Prog Photovolt Res Appl 2004, 12:69.CrossRef 4.