AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Wednesday Sessions
       Session NS+NANO6-WeP

Paper NS+NANO6-WeP12
Optical and Structural Properties of Ball Milled Produced Small Si Particles Embedded into a Sol-Gel Matrix

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: F.J. Espinoza-Beltrán, CINVESTAV-IPN, México
Authors: F.J. Espinoza-Beltrán, CINVESTAV-IPN, México
L.L. Díaz-Flores, CINVESTAV-IPN, México
J.M. Yañez-Limón, CINVESTAV-IPN, México
J. Morales-Hernández, Programa de Posgrado de Ingeniería, UAQ, México
A. Mendoza-Galván, CINVESTAV-IPN, México
J. González-Hernández, CINVESTAV-IPN, México
Correspondent: Click to Email
Nano and micrometric silicon particles have been introduced into SiO@sub 2@ matrix produced by the sol-gel method, using tetraethyl-orthosilicate. The small Si particles were produced by grinding 99.999 % pure silicon granular polyfine in a low energy ball mill. The milling process, for various periods of time, was carried out in air conditions. For that reason, the small particles consist of a Si core surrounded by a SiO@sub x@ cap layer. According to infrared and Raman measurements, the Si core contains molecular structures of the form Si@sub n@, where n is in the range of 6 to 7. >From the position of TO IR active mode the value of x is estimated to be around 1.7. The silicon oxide cap also shows a strong LO mode, normally not observed at normal incidence in the IR absorption of planar SiO@sub 2@ thin layers. An IR line at about 630 cm@super -1@, also indicates that during the milling process, some atomic hydrogen is attached to the silicon particles. Sol-gel layers, with various Si particle sizes and various particle densities were prepared. The structural and optical properties of the as-prepared and heat treated, in the range of 100 to 800°C, powder and film samples were studied. The photoluminescence emission and optical absorption of the Si particles are related with their size and concentration.