{"title":"Formation of Periodic Surface Structures on Semiconductors under Mid-Infrared Free-Electron Laser Irradiation","authors":"Shin-ichiro Masuno, Masaki Hashida, Heishun Zen","doi":"10.1541/ieejfms.143.320","DOIUrl":null,"url":null,"abstract":"In understanding the formation mechanism of laser-induced periodic surface structures (LIPSS), the dependence of the LIPSS formation threshold fluence F// on the material properties is crucial. In this work, the LIPSS generated upon the irradiation of various semiconductor materials with a train of 11.4 µm femtosecond laser pulses were examined. The laser source was a Mid-infrared free-electron laser (MIR-FEL). Eight semiconductor substrates (i.e., Si, Ge, ZnO, SiC-4H, GaP, GaN, CdTe, and SiO2) were used as the targets. On Si, Ge, SiC-4H, and GaN, the LIPSS were oriented parallel to the MIR-FEL polarization with interspaces of 1/8 to 1/4 of the MIR-FEL wavelength λFEL. These interspaces tended to match the wavelength of the second harmonic of the MIR-FEL light propagating in the substrates. The obtained F// were relatively correlated with the bandgap energies of materials, as were those for near-infrared femtosecond lasers. Another type of LIPSS oriented perpendicular to the MIR-FEL polarization with interspaces of λFEL to λFEL/9 was also observed in the same spot on SiC-4H or GaN at higher fluences than only //-LIPSS was formed.","PeriodicalId":23081,"journal":{"name":"The transactions of the Institute of Electrical Engineers of Japan.A","volume":"18 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The transactions of the Institute of Electrical Engineers of Japan.A","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1541/ieejfms.143.320","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
In understanding the formation mechanism of laser-induced periodic surface structures (LIPSS), the dependence of the LIPSS formation threshold fluence F// on the material properties is crucial. In this work, the LIPSS generated upon the irradiation of various semiconductor materials with a train of 11.4 µm femtosecond laser pulses were examined. The laser source was a Mid-infrared free-electron laser (MIR-FEL). Eight semiconductor substrates (i.e., Si, Ge, ZnO, SiC-4H, GaP, GaN, CdTe, and SiO2) were used as the targets. On Si, Ge, SiC-4H, and GaN, the LIPSS were oriented parallel to the MIR-FEL polarization with interspaces of 1/8 to 1/4 of the MIR-FEL wavelength λFEL. These interspaces tended to match the wavelength of the second harmonic of the MIR-FEL light propagating in the substrates. The obtained F// were relatively correlated with the bandgap energies of materials, as were those for near-infrared femtosecond lasers. Another type of LIPSS oriented perpendicular to the MIR-FEL polarization with interspaces of λFEL to λFEL/9 was also observed in the same spot on SiC-4H or GaN at higher fluences than only //-LIPSS was formed.