Abstract
In this work, nanocrystalline silicon (nc-Si) are deposited in a porous anodic alumina (PAA) matrix by a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) method. The rapid thermal annealing (RTA) effect on morphological and microstructural properties of nc-Si/PAA structure is investigated by SEM, EDX, XRD technique and Raman spectroscopy. Crystallization of the amorphous silicon is obtained after annealing at was 550 °C during a time ranging from 10 to 120 min. The effect of thermal annealing on the optical properties of nc-Si/PAA structure was studied by Spectroscopic Ellipsometry (SE) in the spectral range 0.3–0.8 μm. The Ellipsometric analysis demonstrated the formation of two separate layers during the annealing process. A silicon/alumina alloy as the upper layer and a polysilicon film at the bottom and in contact with the alumina barrier layer. The optical constants, thickness and the composition of each film have been estimated from the SE data using Bruggeman effective medium approximation (BEMA). PL spectroscopy was used to investigate the bandgap energy of nc-Si embedded within the PAA matrix, the origin of emission PL spectra as well as the observed red-shift have been discussed.
•Nanocrystalline Si were grown into PAA template by a RF-PECVD method.•Effect of the annealing time on the microstructure and the surface morphology of nc-Si/PAA layers.•Optical constants and bandgap energy were derived from the fitted SE data of nc-Si/PAA microstructure.•PL properties of the confined Si nanocrystals on PAA layer are investigated with PL technique.