Nano-crystalline Si/SiO 2 multilayers were prepared by alternately changing the ultra-thin amorphous Si film deposition and the in situ plasma oxidation process followed by the post-annealing treatments. Well-defined periodic structures can be achieved with 2.5 nm thick SiO 2 sublayers. It is shown that the size of formed nano-crystalline Si is about 3 nm. Room temperature electroluminescence can be observed and the spectrum contains two luminescence bands located at 650 nm and 520 nm. In order to improve the hole injection probability, p-i-n structures containing a nanocrystalline Si/SiO 2 luminescent layer were designed and fabricated on different p-type substrates. It is found that the turn-on voltage of p-i-n structures is obviously reduced and the luminescence intensity increases by 50 times. It is demonstrated that the use of a heavy-doped p-type substrate can increase the luminescence intensity more efficiently compared with the light-doped p-type substrate due to the enhanced hole injection.

Amorphous Si/SiO(2) multilayers (MLs) on silicon wafers were fabricated in a plasma enhanced chemical vapor deposition system via cycles of silicon deposition and plasma oxidation. The structural and optical properties of the MLs were characterized using transmission electron microscopy, Raman scattering and room temperature photoluminescence (PL) measurements. Intermediate phase silicon structure (IPSS), which is intermediate in order between the continuous random network amorphous phase and the well ordered crystalline phase, was found in the a-Si sublayers around the crystallization onset temperature. Red-near infrared wavelength region PL from recombination via structural defects inside the IPSS and Si = O at the surface of both nanocrystal Si (nc-Si) and IPSS was observed. In the samples with IPSS and nc-Si coexisting, the IPSS was found to be about five times more efficient as regards PL than nc-Si.