Abstract It is known that bulk silicon is the dominant semiconductor material in microelectronics. However, its use in reliable and low cost integrated circuits (IC) fabrication which carry out opto-electronic functions has not been appropriate due to the fact that silicon is an indirect band gap material. Observation of luminescence in porous silicon seemed to solve the physical inability of the silicon (Si) to act as light emitter; however its poor chemical stability, weak robustness and luminescence degradation made it unsuitable for such applications. Other Si-based materials such as hydrogenated silicon rich oxynitride, Si/SiO2 multilayers, and silicon rich oxide (SiOx, x<2) films have been reported to solve the physical incapacity of silicon to act as light emitter. The key for the excellent light emission properties of these materials are the embedded silicon nanoparticles (Si-nps). With this approximation the quantum confinement of carriers is maximized, the probability of radiative recombination is improved, and the emission wavelength is shifted to the visible range and controlled with the Si-np’s size. These nanometre-sized silicon particles either embedded in a SiO2 or Si3N4 matrix have shown a strong and stable luminescence seeming as a better alternative for light emitting devices (LED’s) fabrication. In this thesis, silicon rich oxide [SRO, (SiOx, x<2)] films with different silicon excesses were deposited by low pressure chemical vapor deposition (LPVCD). Besides, Si implanted SRO (SI-SRO) films were also fabricated. Si-nps in these films were created after a thermal annealing at high temperature (1100 and 1250º C). The composition, microstructure and optical properties of these SRO and SI-SRO films were analyzed as a function of the different technological parameters, such as silicon excess, Si ion implantation dose, and thermal annealing temperature. Once the microstructure, composition as well as the optical properties of these materials is known, SRO films which exhibited the best photoluminescent (strongest PL) properties were chosen in order to analyze their electrical and electro–optical properties. Simple Metal–Oxide–Semiconductor (MOS) structures using the SRO films as the dielectric layer were fabricated for these studies. SRO films with Si-excess of ~4.0 and ~2.2 at.% and thickness ranging from 24 to 80 nm were deposited. The conduction mechanism in these films is analyzed by making use of trap assisted tunnelling (TAT) in low ele