Silicon nano particles: Surface characterization, defects and electronic properties

Abstract

Nano scaled silicon particles (nc‐Si) having a diameter of about 3 to 9 nm were synthesized by direct reduction of SiCl4 with H2 in a LaCl3 matrix by a vapour deposition (CVD) route. The particles were characterized by diffuse reflection fourier transform spectroscopy (DR/FT‐IR), photoluminescence (PL), electron paramagnetic resonance (EPR) and microwave detected photo induced current transient spectroscopy (MD‐PICTS). EPR measurements identified dangling bond defects on the surface of as‐prepared nc‐Si particles in the LaCl3 matrix. The number of dangling bonds significantly decreases upon extraction of the nc‐Si with ethanol. As expected, the dangling bonds disappear completely after treatment with 1% HF solution. A strong correlation between presence of dangling bond defects and electronic properties was found. The temperature dependent photoconductivity in conjunction with the EPR and PL results allowed us to analyze the defect structure of the nc‐Si particles. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A General Route to Efficient Functionalization of Silicon Quantum Dots for High‐Performance Fluorescent Probes

“…Jing Wang , Yuexian Liu , Fei Peng , Chunying Chen , Yonghong He , Hui Ma , Lixin Cao , and Shuqing Sun * active and can easily be subjected to oxidation and degradation. [9][10][11][12][13][14][15] In addition, the Si − O linkages have been shown to greatly affect the electronic charge distribution in the SiQDs. [ 16 ] It is therefore essential to further modify the surface of SiQDs to realize their functionalities.…”

“…In particular, the excellent biocompatibility and intrinsic low toxicity characteristics of SiQDs hold great promise for their application in biology and biomedicine 1–8. Generally, the surfaces of freshly synthesized SiQDs are chemically active and can easily be subjected to oxidation and degradation 9–15. In addition, the Si−O linkages have been shown to greatly affect the electronic charge distribution in the SiQDs 16.…”

Hydrogen Terminated Silicon Nanopowders: Gas Phase Synthesis, Oxidation Behaviour, and Si-H Reactivity

“…Acker et al [30] and Henneberg et al [31] reported the reduction of SiCl 4 with hydrogen over metal chlorides, which act as host to give nc-Si. These materials were investigated for their surface dangling bonds, electronic structure, and surface reactivity [32]. Liquid phase synthesis by reduction of chlorosilanes has also been reported as a standard method for the synthesis of silicon nanoparticles [33,34].…”

Electroplated waveguides to enhance DNP and EPR spectra of silicon and diamond particles

“…Nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy are two well-established methods for studying the structure of materials such as silicon-based micro-and nanoparticles (Ha et al, 2019;Hahn et al, 2008;Tasciotti et al, 2008). Direct 29 Si NMR detection is challenging due to the low thermal polarization, low natural abundance of 4.7 %, and long nuclear longitudinal relaxation times of 29 Si (Dementyev et al, 2008).…”