Si Nanocrystals Embedded in SiO₂ Produced by Reactive Sputtering for Light Emission

Abstract

In the present work, we confectioned light emitting SiOx (x<2) samples using reactive sputtering. By controlling the oxygen concentration in the deposition chamber (range from 0.5% up to 10), an excess of silicon was created in the formed silicon oxide films. Only after a thermal annealing (temperatures from 1050ºC to 1100ºC), the samples showed the photoluminescence (PL) effect. Silicon nanocrystals formed during the thermal annealing were the responsible for the observed PL signal when excited with the 488nm line of argon laser. We also performed thermal annealing at 450ºC, using forming gas ambient to passivate the silicon nanocrystals interface. The result was a significant improvement in PL signal. Furthermore, the Rutherford Backscattering Spectrometry experiment showed that the deposition time is an important parameter to create the silicon excess and achieve light emission.