Optical stimulated thermoluminescence in Silicon Rich Oxide nanostructured films

In this work, it is study thermoluminescent phenomena (TL) optically stimulated with UV radiation in Silicon Rich Oxide (SRO) nanostructured thin films. The experimental samples used were thin films of this composite deposited by Low Pressure Chemical Vapor Deposition (LPCVD) over a n-type silicon substrate, this samples were fabricated using different flow ratios of precursory gases silane and nitrous oxide R0=SiH4/N₂O during the deposition and were given posterior thermal treatment which gave place to the formation of different sized nanoparticles, that are attributed to the luminescent activation mechanism in this material. The silicon excess was controlled by the ratio of the gases used in the deposition process and in this way SRO films with 12, 8 and 6% silicon excess were obtained. The glow-curves experimentally obtained were submitted to analysis using different models in order to obtain important thermoluminescent parameters. The luminescence spectra of SRO show two wavelength regions of emission; one in the blue part and one in the red part of the emission spectrum. The emission in the blue part is related to defects in the SiO lattice. About the origin of the red luminescence there is still a controversy. One model assumes that the red luminescence stems from Si nano particles and another model assumes that defects at the interface of SiO bulk with the Si nano particle are responsible for the red luminescence. Finally is intended to provide favorable conditions for the development of a UV dosimeter with this material.