Papers by Keyword: Si Nanoparticles

Abstract: In this paper the fractures appeared in the surface of nanoparticle silicon anode for lithium-ion batteries was explored. The changes of nanoparticle silicon anode before and after cycling were charactered using SEM, XRD,Cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS). The result indicates that the electrode cracking occured in the cycling process , the CV, EIS and discharge specific capacity curves proved the fractures could lead to the degradation of the electrochemical performance.

Abstract: The properties of SiOx layer prepared by magnetron sputtering is studied by photoluminescence Auger and SIMS methods. The depth distribution of emission characteristics and chemical composition is obtained. It is shown that as-sputtered SiOx layers are non-emitted and characterized by homogeneous enough chemical composition. High-temperature annealing in nitrogen atmosphere stimulates not only the Si nanocrystal formation but also the redistribution of silicon and the appearance of Si depleted region near layer-substrate interface. The last process is found to be dependent on excess Si content. It is found that decrease of silicon content in the depth of annealed layers is followed by the decrease of particle sizes that is proved by the blue shift of photoluminescence maximum. The possible reasons of the appearance of Si depleted region are discussed.

Abstract: The properties of SiOx layer prepared by magnetron sputtering is studied by photoluminescence Auger and SIMS methods. The depth distribution of emission characteristics and chemical composition is obtained. It is shown that as-sputtered SiOx layers are non-emitted and characterized by homogeneous enough chemical composition. High-temperature annealing in nitrogen atmosphere stimulates not only the Si nanocrystal formation but also the redistribution of silicon and the appearance of Si depleted region near layer-substrate interface. The last process is found to be dependent on excess Si content. It is found that decrease of silicon content in the depth of annealed layers is followed by the decrease of particle sizes that is proved by the blue shift of photoluminescence maximum. The possible reasons of the appearance of Si depleted region are discussed.

Abstract: In the present work, we investigate the photoluminescence (PL) and structural properties of Si nanoparticles embedded in SiO2 matrix. Si-rich silicon oxide (SRSO) films with Si concentration of 39% were synthesized by reactive RF magnetron sputtering. Annealing was performed at temperatures between 600°C and 1100°C in N2 ambient for 2h to precipitate Si nanoparticles from oxide matrix. Near infrared photoluminescence around 750nm can be clearly observed even in the as-deposited films, which indicates the existence of Si nanoparticles in films. The structural properties were analyzed by infrared absorption and Raman spectra. It is found that the structural properties strongly affect the PL properties of Si nanoparticles embedded in SiO2 matrix.