Thin films of silicon nanoparticles embedded in Al2O3 matrices

Silicon nanoparticles embedded in a host matrix of Al2O3 thin film about 26 0 nm thick were prepared by using the pulsed laser deposition method. The l aser target consisted of a small silicon wafer glued onto the surface of a circular Al2O3 plate, which was set to rotate uniformly when laser-ablating . TEM and EDS results showed that the films consisted of silicon nanopartic les in the form of nanocrystals with diameters of less than 6 nm dispersed in the amorphous Al2O3 matrices. Strong PL from the as-prepared and the ann ealed samples was observed. The SIMS depth profile of the silicon content o f the film indicated that the silicon nanoparticles in the Al2O3 matrices w ere arranged in fairly well demarcated thin layers sandwiched between layer s of the host material. FTIR results evidently suggested that the encapsula ting amorphous Al2O3 material forms a good host for the prevention of atmos pheric oxidation of the silicon nanoparticles. However, prolonged annealing can cause the silicon nanoparticle surface interfacing the host material t o be oxidized by the oxygen mostly from the Al2O3 molecules and be bonded t o the Al or O-Al bonds.