The concentration of H2O2 influences the nucleation and motility of Ag particles, which leads to the formation of different porous structures within the nanowires. When H2O2 concentration is too high, the excessive Ag+ would be produced, and they renucleate to form numerous Ag particles Selleck NSC 683864 which catalyze H2O2 reduction and induce excessive silicon dissolution. That is to say, the polishing would be induced under high H2O2 concentration of the HF/AgNO3/H2O2 system. Figure 7 Schematic illustration of the formation process of PSiNWs through

MACE method in HF/H 2 O 2 /AgNO 3 system. (A) Ag nanoparticles deposit on silicon surface at the beginning. (B) SiNWs grow with the migration of Ag particle, and some Ag+ ions renucleate throughout the nanowires. (C) Numerous perpendicular pore channel form with the migration

of renucleated Ag particle. (D) Porous structure can be Fludarabine price obtained with the removal of Ag0. Conclusion This work has demonstrated p53 activator a simple MACE method for successfully fabricating lightly doped porous silicon nanowires at room temperature. The effects of H2O2 concentration on nanostructure of moderately and lightly doped SiNWs were investigated. The results indicate that the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads different porous structure within the nanowires. In the HF/AgNO3/H2O2 etching Rutecarpine system, the H2O2 species replaces Ag+ as the oxidant and the Ag nanoparticles work as catalyst during the etching. A mechanism based on the lateral etching which is catalyzed by Ag particles with the motivation of H2O2 reduction is proposed to explain the formation of PSiNWs. The simple etching system not only synthesizes large-scale moderately doped single crystalline PSiNWs, but can also fabricate lightly doped ones, which can open up exciting opportunities

in a wide range of applications. For example, the vertically aligned nanowires with a high surface area can be exploited as a high-capacity electrode for supercapacitors. The deep quantum confinement effect and biodegradability feature of the porous silicon nanowires may enable interesting applications in optoelectronics and drug delivery. Acknowledgement Financial supports of this work from the Specialized Research Fund for the Doctoral Program of Higher Education of China (20135314110001) and the Program for Innovative Research Team in University of Ministry of Education of China (IRT1250) were gratefully acknowledged. References 1. Schmidt V, Riel H, Senz S, Karg S, Riess W, Gösele U: Realization of a silicon nanowire vertical surround-gate field-effect transistor. Small 2006, 2:85–88.CrossRef 2. Hochbaum AI, Chen R, Delgado RD, Liang W, Garnett EC, Najarian M, Majumdar A, Yang P: Enhanced thermoelectric performance of rough silicon nanowires. Nature 2008, 451:163–167.CrossRef 3.