Aspect ratio dependent cold cathode emission from vertically aligned hydrophobic silicon nanowires. (January 2018) - Ray, U.
Graphical abstract: Highlights: Vertically aligned silicon nanowires (SiNWs) were grown on silicon substrate. The aspect ratio was tailored by varying etching time. The as prepared sample was made superhydrophobic by simple chemical treatment. As prepared samples show good cold emission property. Abstract: The silicon nanowires (SiNWs) were grown by a simple metal assisted chemical etching method on silicon substrate. The length and the aspect ratio of the as-prepared SiNWs were varied by varying the etching time. The as-prepared samples were then modified by hydrofluoric acid treatment. All the pure and modified samples were characterized by field emission scanning electron microscope (FESEM), Fourier transformed infrared (FTIR) and UV–vis spectroscopy. The surface wettability of the samples, both pure and modified with HF, was studied by measuring the contact angle of two different liquids and their respective surface energies were calculated using Owens method. The cold cathode emission characteristics of the modified sample have been studied using a high vacuum electron field emission set up. It has been shown that the samples give efficient cold emission suggesting possibility of existence of hydrophobic cold emitter. Also it is shown that the emission characteristic gets significantly enhanced with increasing aspect ratio of the wires giving almost a hundred percent betterment in the turn on field.