Photoluminescence from β-SiC nanocrystals embedded in SiO_2 films prepared by ion implantation

摘要

Photoluminescence from β-SiC nanocrystals embedded in SiO_2 films at room temperature has been studied. The β-SiC nanocrystals were formed by carbon implantation into Si substrate at 35 keV with various dose, followed by post-implantation annealing at 1200 ℃ for 30 min in Ar ambient. Thermal dry-oxidation of the annealed samples at 1050 ℃ for 3 h was performed to form β-SiC nanocrystals embedded in SiO_2 films. The composition and chemical state of C and Si atoms were characterized by non-Rutherford backscattering spectrometry and Fourier transform infrared spectroscopy, respectively. FTIR results show that β-SiC nanocrystals were formed in SiO_2 films, and the amount of β-SiC nanocrystals in SiO_2 films increases with increasing of implanted dose. The photoluminescent properties of the samples were measured at room temperature with a Hitachi F4010 fluorescence spectrophotometer using a xenon lamp as an excitation source (300 nm). Two distinguishable PL bands located at around 460 and 535 nm were observed in all the samples. The PL intensity significantly depends the implanted dose, and there is a critical implanted dose of 2 x 10~(17) cm~(-2), at which the PL intensity reaches the largest value.