Sandwich-structured thin film of silicon nanoparticles embedded in Al2O3 matrices

Abstract

Silicon nanoparticles embedded in the host matrix of anAl2O3 thin film, with a thickness of about 260 nm, were prepared byusing the pulsed laser deposition method. The laser target consisted of asmall silicon wafer glued onto the surface of a circular Al2O3plate, which was set to rotate uniformly when laser-ablating. TEM and EDSresults showed that the films consisted of silicon nanoparticles in theform of nanocrystals with diameters of less than 6 nm dispersed in theamorphous Al2O3 matrices. A secondary ion mass spectroscopy depthprofile of the silicon content of the film indicated that the siliconnanoparticles in the Al2O3 matrices were arranged in fairly welldemarcated thin layers sandwiched between layers of the host material.FTIR results evidently suggested that the encapsulating amorphousAl2O3 material forms a good host for the prevention of atmosphericoxidation of the silicon nanoparticles. However, prolonged annealing cancause the silicon nanoparticle surface interfacing the host material to beoxidized by the oxygen mostly from the Al2O3 molecules and to bebonded to the Al or O-Al bonds.