Investigation of mechanism of bias sputtering causing autocloning

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CdS two-dimensional photonic crystals were fabricated by using double-interference exposure and rf sputtering. A suppressed photoluminescence spectrum was observed normal to the surface in the wavelength range other than in-plane resonance.We developed a dry-etching process to form holes with diameters of 5 microns to 50 of microns in 7-micron thick a-Si/SiO_2 three-dimensional photonic crystal layers fabricated on InP substrates by the autocloning method. We also demonstrated wet-etching processes to remove damaged surfaces of exposed InP substrates and selectively grew In_<0.62>Ga_<0.38>As/In_<0.45>Ga_<0.31>Al_<0.24>As multiple quantum well by molecular beam epitaxy in a region surrounded by a-Si/SiO_2 three-dimensional photonic crystals. Polarization dependence was observed in a spontaneous emission transmitted at 75 microns in a lateral direction in the photonic crystal layer.We observed a photoluminescence(PL) spectrum at room temperature that had a peak with full width of half maximum(FWHM) of 0.38 eV near the bandgap energy of 3.2 eV from an Si:SiO_2 sputtered film without annealing. Blue-light emission could be seen by the naked eye. A low-intensity PL peak with FWHM of 0.20 eV was also observed at around 1.6 eV. We have already demonstrated that our method automatically forms Si clusters contributing to visible emission. Our results did not contradict the well-founded conjecture that there were two mechanisms of emission from Si clusters : emission at 1.6 to 1.7 eV due to the surface state of the oxidized Si nanocrystals and emission at the bandgap energy originating from the quantum confinement effect. Blue-light-emission from Ti:SiO_2 sputtered films was also observed at room temperature without annealing. The peaks of PL spectra were located at 3.03 to 3.05 eV and FWHM were 0.38 to 0.40 eV, which were almost the same in samples having different energies of absorption edge.