Nanosize crystalline silicon films are fabricated by using highly hydrogen-diluted silane as the reactive gas and activated with rf+dc double-power sources, in a conventional plasma-enhanced chemical-vapor-deposition system. The structure of the deposited films as studied by means of high-resolution electron microscopy, Raman scattering spectra, x-ray-diffraction pattern, IR transmission spectra, and ultraviolet ray analysis. The results show that there are many novel structural features and new physical properties for these nanosize crystalline silicon films. In particular, it is found that the optical-absorption coefficient α is higher than that of a-Si:H and μc-Si:H films, the room-temperature conductivity σd has the value of 10−3–10−1 Ω−1 cm−1, and the hydrogen content CH in nc-Si:H films is higher than 30 at. %. The nc-Si:H films have their peculiar features which are different from both a-Si:H and μc-Si:H films.

Three photoluminescence (PL) bands at 340–370, 400–430, and 740 nm were observed at room temperature in a-Si:H:O films fabricated by plasma enhanced chemical vapor deposition without any postprocessing. The violet-blue emission is very strong and stable, and its intensity is closely related to the oxygen content in the films, which can be controlled by the applied dc biases on the sample substrates during deposition. The first two PL peaks are ascribed to Si–O related species, and the last one to the quantum size effect of the nanocrystallites embedded in the a-Si:H:O matrix.

We report in this letter the observation of visible photoluminescence (PL) at room temperature from hydrogenated nanocrystalline silicon (nc-Si:H)/amorphous silicon (a-Si:H) multilayers (MLs) prepared in a plasma enhanced chemical vapor deposition system without any postprocessing. The PL peak wavelength can be controlled, blueshifting from 750 to 708 nm, through reducing the width of the nc-Si:H sublayers from 4.0 to 2.1 nm. Quantum size effect in nc-Si:H sublayers of the ML is responsible for the emission above the band gap of bulk crystal Si.

We report in this letter the observation of visible photoluminescence (PL) at room temperature from nanocrystallites embedded in hydrogenated amorphous silicon films, which are prepared in a plasma enhanced chemical vapor deposition system by using strong hydrogen-diluted silane as the reactant gas source, without any post-processing. The PL is attributed to the radiative recombination process of carriers in the nanocrystallites, and the quantum size effect is responsible for the emission above the band gap of bulk crystal Si. The critical deposition parameters of this type of film are identified.

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