Understanding the Parameters Affecting the Photoluminescence of Silicon Nanoparticles

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• 作者：Manuel J. Llansola Portol茅s ; Reinaldo Pis Diez ; Mar铆a L. Dell鈥橝rciprete ; Paula Caregnato ; Juan Jos茅 Romero ; Daniel O. M谩rtire ; Omar Azzaroni ; Marcelo Ceol铆n ; M贸nica C. Gonzalez
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：May 24, 2012
• 年：2012
• 卷：116
• 期：20
• 页码：11315-11325
• 全文大小：500K
• 年卷期：v.116,no.20(May 24, 2012)
• ISSN：1932-7455

文摘

Silicon nanoparticles of 1鈥? nm size (SiNPs) were synthesized by a bottom-up (BU) approach involving a chemical wet method. The contribution of different emitters to the overall excitation鈥揺mission matrix was analyzed on the assumption that pure substances existing in a unique form show an excitation wavelength-invariant emission spectrum. The occurrence of emitters differing in size and aggregation was supported by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), time-resolved single photon counting, and time-resolved anisotropy experiments. The effect on photoluminescence (PL) of the particle surface oxidation as a result of aging is studied and compared to that of surface oxidized particles obtained by a top-down (TD) approach following an electrochemical method with HF etching. Surface oxidation to SiO_x seems to introduce two different effects on the SiNP PL. An emission originated in surface states associated to SiO_x was identified and observed for SiNPs synthesized by both BU and TD approaches. Blue-shifted excitation鈥揺mission spectra associated to a silicon core in embedded SiO_x nanostructures were also identified. Theoretical studies were carried out to help understand the observed results.