One-step formation of nanostructures on silicon surfaces using pure hydrogen-radical-initiated reactions



One-step formation of silicon nanowires, sheets, and texture surface on a silicon substrate has been achieved using hydrogen-radical etching reactions. Metallic tungsten and for comparison purposes a tungsten hot wire, were used as catalysts for the hydrogen-molecular cracking. It was shown that a variety of surface structures on silicon such as inverted pyramid texture, V-groove texture, dense silicon nanowire growth over texture, and nanosheet structure can be obtained by controlling the process conditions. The obtained results suggested that the formation of nanotungsten silicide particle is an essential prerequisite to obtain these structures. The particles work as an etching mask against hydrogen-radical etching, as well as a catalyst for vapor–solid–solid (VSS) growth. SEM, TEM, micro-RAMAN, and XPS were used for the analysis of the hydrogen-radical-treated Si samples. The Si nanowires growth model, as well as the texturing mechanism initiated by hydrogen-radical treatment of Si surface in the presence of tungsten nanoparticle is discussed. It is concluded that the proposed acid-free method, which is based on a modification of Si surfaces only by hydrogen radicals, can be considered as a “green” technology approach, which can be used for the cost-effective fabrication of silicon nanostructures, which can be considered as a base for several types of advanced devices in the future.