Luminescent Silicon Oxycarbide Thin Films via Hot-wire CVD using Tetraethyl Orthosilicate: Role of the Chamber Pressure and Post-deposition Annealing

We report the obtention of luminescent silicon oxycarbide thin films deposited by Hot-wire chemical vapor deposition technique using tetraethyl orthosilicate as precursor. Additionally, we study the effect of the chamber pressure and the post-deposition thermal annealing in oxygen and hydrogen environments on the properties of the films. All the as-deposited samples showed an intense and wide emission band centered in the blue region. The samples deposited at 0.3 and 0.5 Torr presented a high surface uniformity. The X-ray diffraction measurements did not show the presence of nanocrystalline phase, so, we attributed the emission bands to defects in the silicon oxycarbide matrix, mainly related to oxygen deficiency centers, and to hydrogen and carbon-related defects. After the thermal annealing in oxygen and hydrogen, the samples showed a significative reduction in the emission intensity because of radiative defects passivation.