Effect of NaOH solution concentration on the quality of controllable silicon nanowires array fabrication

Abstract

Ordered silicon nanowires array with large area is produced on the surface of a silicon substrate by using anodic aluminum oxide (AAO) assisted chemical wet-etching. To improve the quality and area of silicon nanowires array, the AAO whose surface is sputtered with about 15 nm thick gold nanofilm, is dissolved in NaOH solution of different concentrations. The NaOH concentration eventually affects the physical structure of the gold nanofilm floating on the surface of the solution. The higher the concentration of NaOH, the greater is the surface tension, the flatter is the gold film, the larger is the distribution area and the better is the quality of the nanowire array. However, as the concentration reaches 2.5 mol L−1, excessive surface tension seriously damages the integrity of the gold film, a happening which cannot guarantee the realization of a large area for the array. The experimental results show that NaOH concentration is one of the most important factors affecting the quality and area of silicon nanowires array. Suitable configuration of NaOH solution concentration during the fabrication process effectively increases the quality and controllable growth area of silicon nanowires array.