Research Of The Structure And Antireflective Property Of Silicon Nanowires Array

At present, it is a very important way to prepare silicon nanowire array by two-step metal assisted chemical etching method. This paper first studies the factors that affect the structure of silicon nanowire array deeply and learns how to use these factors to regulate the structure. Then the antireflective property of silicon nanowire array is studied based on the optimization of the structure.Firstly, the paper studies the factors affecting the morphology of the silver layer deposited on the surface of silicon. By changing the parameters, such as concentration of hydrofluoric acid, silver nitrate and the deposition time of silver particles, the related changes of the morphology of silver deposition are studied. There is an equilibrium deposition. The length of the silicon wire increases with the etching time when the actual deposition is below the equilibrium deposition and decreases when above it. The diameter of silicon nanowire is between 100-200 nm and decreases along with the amount of silver deposition.Secondly, the paper determines the appropriate etching solution. The concentration of hydrofluoric acid and hydrogen peroxide of the etching liquid are 4.8 mol/L and 0.4 mol/L respectively. The effects of etching time on the structure of silicon nanowire arrays are also studied. With the growing of etching time, Silicon nanowire length linearly increases, the diameter decreases and the surface aggregation increases.Subsequently, the paper studies the effects of post treatments on the structures of silicon nanowire arrays. One treatment is to use potassium hydroxide solution to corrode the silicon nanowire array again. Another treatment is thermal oxidation in tube furnace followed by hydrofluoric acid corrosion. The changes of silicon nanowire array is related to the time. The influences of these two treatments on the silicon nanowire arrays are studied.Finally, based on the above regulation and adjustment of the structure of silicon nanowire array, a series of silicon nanowire arrays with different structures are prepared. Then the antireflective property of these silicon nanowire arrays is studied. The reflection decreases with the growing length and increases with the growing of fill ratio, surface aggregation and irregularity. However, The average reflection between the wavelength of 300-800 nm is about 1% to 4%.