In this Letter, silver（Ag） hierarchical nanostructures grown on black silicon（BS） are used as the catalyst and a surface-enhanced Raman scattering（SERS） detector integrated in a microfluid. The BS is fabricated ...In this Letter, silver（Ag） hierarchical nanostructures grown on black silicon（BS） are used as the catalyst and a surface-enhanced Raman scattering（SERS） detector integrated in a microfluid. The BS is fabricated via femtosecond laser ablation in an atmosphere of sulfur hexafluoride, and then hydrogenated with hydrofluoric acid. As formed, the BS substrate directly acts as a reducing template to grow silver hierarchical nano-structures.Particularly, Ag-BS composite micro/nano-structures can be in-situ constructed in silicon-based microchannels.These structures simultaneously serve as integrated catalytic reactors and a SERS substrate for sensing. The sensitivity is tested to be as low as 10-8mol∕L using Rhodamine 6G.展开更多
In this Letter, we have demonstrated significant electric field induced（EFI） optical rectification（OR） effects existing in the surface layers of germanium（Ge） and measured the distributions of EFI OR signals alo...In this Letter, we have demonstrated significant electric field induced（EFI） optical rectification（OR） effects existing in the surface layers of germanium（Ge） and measured the distributions of EFI OR signals along the normal directions of surface layers of Ge samples. Based on the experimental results, the ratios of the twoe-order susceptibility components χ2 effTzzz∕χe2 effTeffective secondzxxfor Ge（001）, Ge（110）, and Ge（111） surface layers can be estimated to be about 0.92, 0.91, and 1.07, respectively. The results indicate that the EFI OR can be used for analyzing the properties on surface layers of Ge, which has potential applications in Ge photonics and optoelectronics.展开更多
The depth profile of electric-field-induced（EFI） optical rectification（OR） and EFI Pockels effect（PE） in a Si（110） crystal are investigated. The results show that EFI OR and PE signals are very sensitive to th...The depth profile of electric-field-induced（EFI） optical rectification（OR） and EFI Pockels effect（PE） in a Si（110） crystal are investigated. The results show that EFI OR and PE signals are very sensitive to the electric field strength in the surface layers of the Si crystal. Theoretical formulas that include the electric field parameters and the widths of the space-charge region are presented and agreed very well with the experimental results. The experiments and simulations indicate that EFI OR and PE are potential methods for researching the surface/interface properties along the depth direction in centrosymmetric crystals such as Si.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos. 61307119 and 61235004
文摘In this Letter, silver（Ag） hierarchical nanostructures grown on black silicon（BS） are used as the catalyst and a surface-enhanced Raman scattering（SERS） detector integrated in a microfluid. The BS is fabricated via femtosecond laser ablation in an atmosphere of sulfur hexafluoride, and then hydrogenated with hydrofluoric acid. As formed, the BS substrate directly acts as a reducing template to grow silver hierarchical nano-structures.Particularly, Ag-BS composite micro/nano-structures can be in-situ constructed in silicon-based microchannels.These structures simultaneously serve as integrated catalytic reactors and a SERS substrate for sensing. The sensitivity is tested to be as low as 10-8mol∕L using Rhodamine 6G.
基金supported by the National Natural Science Foundation of China(Nos.61474055 and 60976043)the National 863 Program of China(No.2009AA03Z419)
文摘In this Letter, we have demonstrated significant electric field induced（EFI） optical rectification（OR） effects existing in the surface layers of germanium（Ge） and measured the distributions of EFI OR signals along the normal directions of surface layers of Ge samples. Based on the experimental results, the ratios of the twoe-order susceptibility components χ2 effTzzz∕χe2 effTeffective secondzxxfor Ge（001）, Ge（110）, and Ge（111） surface layers can be estimated to be about 0.92, 0.91, and 1.07, respectively. The results indicate that the EFI OR can be used for analyzing the properties on surface layers of Ge, which has potential applications in Ge photonics and optoelectronics.
基金supported by the National Natural Science Foundation of China(Nos.61474055and 60976043)the National 863 Program of China(No.2009AA03Z419)
文摘The depth profile of electric-field-induced（EFI） optical rectification（OR） and EFI Pockels effect（PE） in a Si（110） crystal are investigated. The results show that EFI OR and PE signals are very sensitive to the electric field strength in the surface layers of the Si crystal. Theoretical formulas that include the electric field parameters and the widths of the space-charge region are presented and agreed very well with the experimental results. The experiments and simulations indicate that EFI OR and PE are potential methods for researching the surface/interface properties along the depth direction in centrosymmetric crystals such as Si.
