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a - Si : H ∕ Si O 2 multilayers prepared by plasma-enhanced chemical-vapor deposition exhibit a luminescence band around 760nm, which is quenched after a dehydrogenation process. Subsequent hydrogen plasma annealing (HPA) treatments are carried out, and the luminescence is then recovered. The effects of HPA are investigated as functions of hydrogen annealing time and temperature. Fourier transform infrared spectroscopy and Raman-scattering spectroscopy are used to study the change of the microstructures and bonding configurations due to the HPA treatments. It is indicated that the atomic hydrogen cannot only diffuse into the film to reduce the density of nonradiative recombination centers but can also relax the film network and improve the microstructure order of the a-Si:H sublayers. All these factors are believed to contribute to the recovery of the luminescence signals of the a-Si:H∕SiO2 multilayers.

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The evolution of photoluminescence ͑PL͒ at room temperature from a-Si:H/SiO 2 to nc-Si/SiO 2 multilayers was observed through step-by-step post-treatment. It is found that the Si dangling bonds caused by dehydrogenation result in an intensified PL peak at 700 nm. The competition between the role of Si dangling bonds and nc-Si is the origin of the weaker PL band, including two peaks at 700 and 775 nm. The enhancement of PL intensity of the peak at 775 nm is induced by the increase of the number of nc-Si and oxygen-related defects saturated by Si-O-Si within the Si/SiO 2 interface. The relation between the evolution of PL and microstructure of the samples is discussed in detail.

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