Generation of microstructures and extreme sub-wavelength laser-induced periodic structures on the Si surface using N2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {N}_{2}$$\end{document} nanosecond pulsed laser for the reduction of reflectance

A detailed study is done on the growth of microstructures and sub-wavelength laser-induced periodic surface structures (LIPSSs) on silicon (Si) surface using nitrogen (N2)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {N}_{2})$$\end{document} nanosecond (ns) laser processing in air. The period of LIPSS is found to be as small as 37 nm which is close to λ/9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\lambda /9$$\end{document} times the irradiated laser wavelength (337 nm). In the optimised condition the sums total of reflectance (specular reflectance +\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document} diffuse reflectance) was found to be as low as 10% for a broad wavelength range. The reflectance behaviour has been correlated with the morphology of the generated microstructures.