Fabrication of porous silicon nanowires by MACE method in HF/H2O2/AgNO3 system at room temperature.

Shaoyuan Li,Xiuhua Chen,Wenjie Zhu,Yongyin Xiao,Yang Zhou,Wenhui Ma,Feng Wei,Mingyu Ma

doi:10.1186/1556-276x-9-196

Abstract

In this paper, the moderately and lightly doped porous silicon nanowires (PSiNWs) were fabricated by the ‘one-pot procedure’ metal-assisted chemical etching (MACE) method in the HF/H2O2/AgNO3 system at room temperature. The effects of H2O2 concentration on the nanostructure of silicon nanowires (SiNWs) were investigated. The experimental results indicate that porous structure can be introduced by the addition of H2O2 and the pore structure could be controlled by adjusting the concentration of H2O2. The H2O2 species replaces Ag+ as the oxidant and the Ag nanoparticles work as catalyst during the etching. And the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads to formation of different porous structure within the nanowires. A mechanism based on the lateral etching which is catalyzed by Ag particles under the motivation by H2O2 reduction is proposed to explain the PSiNWs formation.

Highlights

Silicon nanowires (SiNWs) have widely attracted attention due to their unique physical and chemical properties and potential applications in optoelectronics [1], thermoelectrics [2,3], energy conversion and storage [4,5,6], and biomedicine [7,8]
silicon nanowires (SiNWs) show an obvious morphology difference when H2O2 is introduced into the HF/AgNO3 system, the top of the nanowires gather together, which could be attributed to the degenerate rigidity and increased strain with the presence of numerous porous structures [23,29]
The results indicate that the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads different porous structure within the nanowires

Summary

Introduction

Silicon nanowires (SiNWs) have widely attracted attention due to their unique physical and chemical properties and potential applications in optoelectronics [1], thermoelectrics [2,3], energy conversion and storage [4,5,6], and biomedicine [7,8]. The doped type and concentration, fabrication methods and etching temperature have an important effect on the morphology of silicon nanowire. Yang et al [23] have reported that the MPSiNWs were fabricated by 1-MACE with highly doped p-type silicon at temperature of 25°C to 50°C. To et al [22] reported that the MPSiNWs were obtained by etching highly doped n-type silicon with the 1-MACE method. It has been found that the roughness of silicon nanowires is increased with increasing doped level and H2O2 concentration [24,28] For both MACE, the lightly doped silicon wafers are often difficult to obtain PSiNWs [22,23,24,25,26,27]

Methods

Results

Conclusion