Strong Photoluminescence at 1540 nm from Er-doped Amorphous Silicon Oxycarbide: A Novel Silicon Material for Photonic Applications

摘要

The present investigators have previously reported on strong room-temperature luminescence at 1540 nm from erbium-doped amorphous silicon oxycarbide (a-SiC_xO_y:Er) thin films. An enhancement of ～20 times was found for as-grown SiC_(0.5)O_(1.0):Er compared to SiO_2:Er control samples under continuous wavelength (cw) pumping at 496.5 nm. Here, we report the effects of post-deposition annealing on the photoluminescence (PL) properties of Er-doped silicon oxycarbide. The amorphous SiC_xO_y films were grown by thermal chemical vapor deposition (TCVD) at 800℃ and post-deposition annealing was conducted in the temperature range 500-1100℃. The thin films were then implanted with 260keV Er ions and subsequently annealed at 900℃. Strong room-temperature photoluminescence around 1540 nm was observed, with efficient Er~(+3) ion excitation occurring for pumping wavelengths ranging from 460 nm to 600 nm. Modeling of the power dependence of Er luminescence yielded an effective Er excitation cross-section about four orders of magnitude larger than that for a direct optical excitation of Er~(+3) ions. Additionally, Fourier transform infrared spectroscopy (FTIR) studies of post-deposition annealed samples revealed a strong correlation between the Er PL intensity and the C-O bond concentration in the materials. The work suggests a novel method for achieving efficient Er luminescence in Si-based materials through controlled engineering of the Si-C-O system.