Wavelength-Controlled Etching of Silicon Nanocrystals

作者：Nunez Jose R Rodriguez; Kelly Joel A; Henderson Eric J; Veinot Jonathan G C^*

来源：Chemistry of Materials, 2012, 24(2): 346-352.

DOI：10.1021/cm203085f

• silicon nanocrystals
• photoluminescence
• polydispersity
• hydrofluoric acid etching

A detailed investigation of the photochemical etching of silicon nanocrystals (Si-NCs) in aqueous hydrofluoric acid (HF) mixtures is described. By increasing the HF concentration and lowering the pH upon addition of hydrochloric acid (Ha), oxide-embedded Si-NCs were rapidly etched, and photoluminescence (PL) from the resulting hydride-terminated Si-NCs tailored from the near-IR to the yellow/green spectral region by irradiating the reaction mixture at the desired PL wavelength. These results are consistent with a hole-driven etching pathway rather than the chemically induced oxidation/etch pathway commonly exploited for Si nanostructures. The relationship among NC size, polydispersity, and PL was investigated using small-angle X-ray scattering. We suggest the defect density of Si-NCs is a crucial parameter for effective size control via photochemical exciton-mediated HF etching. Improved HF etching methods are expected to enable Si-NC applications through the realization of narrow polydispersity and PL bandwidth.

• 出版日期2012-1-24