Investigation of mechanism of bias sputtering causing autocloning

采用双干涉曝光和射频溅射法制备了CdS二维光子晶体。在除面内共振外的波长范围内，观察到垂直于表面的抑制光致发光光谱。采用干刻蚀法在InP衬底上制备了7微米厚的a- si /SiO_2三维光子晶体，形成直径为5微米至50微米的孔。我们还展示了湿蚀刻工艺去除暴露的InP衬底的损伤表面，并通过分子束外延在a- si /SiO_2三维光子晶体包围的区域中选择性地生长出In_<0.62>Ga_<0.38>As/In_<0.45>Ga_<0.31>Al_<0.24>As多量子阱。在光子晶体层中，在75微米的横向自发发射中观察到偏振依赖性。在室温下，未退火的Si:SiO_2溅射薄膜的光致发光光谱在带隙能量为3.2 eV附近有一个全宽半最大值（FWHM）为0.38 eV的峰。蓝光发射可以用肉眼看到。在1.6 eV左右也观察到一个低强度PL峰，FWHM为0.20 eV。我们已经证明了我们的方法可以自动形成Si团簇，从而产生可见光。我们的研究结果并不与有充分根据的推测相矛盾，即Si团簇有两种发射机制：由于氧化的Si纳米晶体的表面状态而在1.6至1.7 eV发射，以及由于量子限制效应而在带隙能量处发射。Ti:SiO_2溅射薄膜在室温下不退火也能发射蓝光。在吸收边能量不同的样品中，PL谱峰分布在3.03 ~ 3.05 eV， FWHM分布在0.38 ~ 0.40 eV，两者基本一致。

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.