ultra high purity argon gas  (Airgas Inc)

Journal: Small Science

Article Title: Scalable Fabrication of Highly Organized, Horizontally Aligned Sub‐5 nm Silicon Nanowires via Chemical Vapor Etching

doi: 10.1002/smsc.202400627

Figure Lengend Snippet: SERS detection capability of AgNP‐decorated SiNWs/micro‐pit structure. a) Top‐view SEM image of AgNP‐coated SiNWs/micro‐pit arrays prepared as the SERS template for R6G detection. b,c) Magnified SEM images of AgNP‐decorated SiNW arrays organized within micro‐pits. The sub‐10 nm spherical AgNPs are densely distributed across the nanowire arrays. d) Reflectance spectra of the bare Si (100) wafer (gray) and horizontal SiNWs/micro‐pit arrays (red). The hybrid structure exhibits improved light‐trapping performance due to its multiscale surface features. e) Representative SERS spectra of the pristine SiNWs with 10 −6 m R6G (gray) and AgNP‐decorated SiNWs/micro‐pit arrays with 10 −6 m (blue) and 10 −11 m R6G (red). Highly amplified Raman signals can be achieved by incorporating ultrahigh‐density AgNPs. f) Raman map of R6G (10 −6 m ) by targeting the Raman shift at 611 cm −1 (red), 773 cm −1 (blue), and 1360 cm −1 (green), acquired from the white‐dashed area in (a), representing the strong and uniform Raman signal coming out from each Si hierarchical structure. The white‐dashed line area indicates the individual etch pit. The scale bar is 10 μm.

Article Snippet: The chamber was first evacuated to 10 −2 Torr base pressure, and then ultra‐high purity argon (Ar) (99.999%, O 2 < 1 ppm, H 2 O < 1 ppm; Airgas USA, LLC) was introduced until atmospheric pressure.

Techniques: Amplification