Instituto de Ciencias, Centro de Investigaciones en Dispositivos Semiconductores, Benemérita Universidad Autónoma de Puebla, Ed. 103C o D, Ciudad Universitaria, Col. San Manuel, Puebla, Puebla C.P. 72570, México.
Nanoscale Res Lett. 2014 Oct 13;9(1):571. doi: 10.1186/1556-276X-9-571. eCollection 2014.
In this work, we have obtained colloidal solutions of Si nanocrystals (Si-ncs), starting from free-standing porous silicon (PSi) layers. PSi layers were synthesized using a two-electrode Teflon electrochemical cell; the etching solution contained hydrogen peroxide 30%, hydrofluoric acid 40% (HF), and methanol. The anodizing current density was varied to 250 mA cm(-2), 1 A cm(-2), and 1.2 A cm(-2). Thus obtained, PSi was mechanically pulverized in a mortar agate; then, the PSi powders were poured into different solutions to get the final Si-ncs colloidal solutions. The different optical, morphological, and structural characteristics of the colloidal solutions with Si-ncs were measured and studied. These Si-ncs colloidal solutions, measured by photoluminescence (PL), revealed efficient blue-green or violet emission intensities. The results of X-ray diffraction (XRD) indicate that the colloidal solutions are mainly composed of silicon nanocrystallites. The result of UV-vis transmittance indicates that the optical bandgap energies of the colloidal solutions varied from 2.3 to 3.5 eV for colloids prepared in methanol, ethanol, and acetone. The transmission electron microscopy (TEM) images showed the size of the nanocrystals in the colloidal solutions. Fourier transform infrared spectroscopy (FTIR) spectra showed different types of chemical bonds such as Si-O-Si, Si-CH2, and SiH x , as well as some kind of defects.
61.46Df.-a; 61.43.Gt; 61.05.cp; 78.55.-m; 81.15.Gh.
在这项工作中，我们从独立的多孔硅（PSi）层获得了硅纳米晶体（Si-ncs）的胶体溶液。PSi 层是使用双电极聚四氟乙烯电化学电池合成的；蚀刻溶液包含 30%过氧化氢、40%氢氟酸（HF）和甲醇。阳极电流密度分别变化为 250 mA cm(-2)、1 A cm(-2)和 1.2 A cm(-2)。如此获得的 PSi 在玛瑙研钵中机械粉碎；然后，将 PSi 粉末倒入不同的溶液中以获得最终的 Si-ncs 胶体溶液。测量并研究了具有 Si-ncs 的胶体溶液的不同光学、形态和结构特性。通过光致发光（PL）测量的这些 Si-ncs 胶体溶液显示出有效的蓝绿色或紫色发射强度。X 射线衍射（XRD）的结果表明胶体溶液主要由硅纳米晶组成。紫外可见透射率的结果表明，胶体溶液的光学带隙能量在甲醇、乙醇和丙酮制备的胶体中从 2.3 到 3.5 eV 变化。透射电子显微镜（TEM）图像显示了胶体溶液中纳米晶体的尺寸。傅里叶变换红外光谱（FTIR）谱显示了不同类型的化学键，如 Si-O-Si、Si-CH2 和 SiH x ，以及一些类型的缺陷。
61.46Df.-a；61.43.Gt；61.05.cp；78.55.-m；81.15.Gh。
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