Optical properties of silicon nanocrystalline thin films grown by pulsed laser deposition

Nanocrystalline silicon (nc-Si) thin films on silicon substrate have been prepared by using a pulsed laser deposition (PLD). The optical and structural properties of the films have been investigated as a function of deposition temperature, annealing, and oxidation process. When the deposition temperature increased, photoluminescence (PL) intensity abruptly decreased and peaks showed red shift. Annealing process can reduce the number of defect centers. Oxidation has considerable effects upon the formation and isolation of the nanocrystals. These results indicate that the formation mechanism of Si nanocrystals grown by PLD can be explained due to three steps of growth, passivating defect centers, and isolation, sequentially.