Fabrication of three-dimensional photonic crystals by autocloning

我们开发了一种将发光材料与利用射频偏压溅射制造的自克隆光子晶体相结合的技术。(1)通过在自克隆制备的Si/SiO_2三维光子晶体（PhCs）上去除部分Si层，制备了SiO_2/air三维周期结构。采用TEA方法将CdS引入SiO_2/air结构中，形成了CdS/SiO_2的三维周期结构，并观察到了CdS的光致发光现象。通过在TiO_2/air二维周期结构的空隙中引入CdS，在自克隆法制备的TiO_2/SiO_2二维PhCs中蚀刻出部分SiO_2层，制备了TiO_2/air/CdS二维PhCs。测量了垂直于表面的PL，观察到较大的偏振依赖性。(2)在用自克隆方法制备的Si/SiO_2三维光子晶体包围的区域内，利用分子束外延技术开发并演示了选择性生长III-V型化合物半导体活性层的技术。光致发光在光子晶体中横向传输时观察到偏振依赖性。我们认为用射频溅射法制备的Si:SiO_2薄膜适合于自克隆，并尝试将Si:SiO_2薄膜与用自克隆法制备的光子晶体结合。(3)我们发现在有限条件下溅射的Si:SiO_2薄膜在没有退火的情况下发出白光。在SiO_2靶材（直径65 mm）上溅射Si片（直径20 mm）沉积Si:SiO_2薄膜。单片或两片片沉积的样品显示出惊人的宽连续光致发光光谱（波长从0.4 μm以下到0.83 μm以上），并且在室温下可以用肉眼看到白光发射。使用三片或四片沉积的样品不发光，并且我们发现在没有退火的情况下样品有一个有限的硅混合比。

We developed a technology to combine materials having luminescence with photonic crystals fabricated by autocloning utilizing radio frequency (rf) bias sputtering.(1) SiO_2/air three-dimensional (3D) periodic structures were fabricated by removing Si layers partially from Si/SiO_2 3D photonic crystals (PhCs) formed by using autocloning. CdS/SiO_2 3D periodic structures were formed by introducing CdS into the SiO_2/air structures by the TEA method and photoluminescence (PL) was observed from the introduced CdS. TiO_2/air/CdS two-dimensional (2D) PhCs were also fabricated by introducing CdS into the voids of TiO_2/air 2D periodic structures, in which SiO_2 layers were partially etched out from TiO_2/SiO_2 2D PhCs fabricated by using autocloning. PL radiating normal to the surface was measured and large polarization dependence was observed.(2) We developed and demonstrated technologies for selectively growing III-V compound semiconductor active layers by molecular beam epitaxy in a region surrounded by Si/SiO_2 3D photonic crystals fabricated by using the autocloning method. Polarization dependence was observed in photoluminescence transmitted in a lateral direction in the photonic crystal. We thought Si:SiO_2 films fabricated by rf sputtering are suitable for autocloning and tried to combine Si:SiO_2 films with photonic crystals fabricated by autocloning.(3) We found that Si:SiO_2 films sputtered under a limited condition emit white light without annealing. Si:SiO_2 films were deposited by sputtering Si tablets (20 mm diameter) placed on a SiO_2 target (65 mm diameter). Samples deposited using one or two tablets exhibited a surprisingly wide continuous photoluminescence spectra (from wavelengths of below 0.4 μm to over 0.83 μm), and white light emission could be seen by the naked eye at room temperature. Samples deposited by using three or four tablets did not emit, and we found there was a limited Si mixture ratio at which samples emit without annealing.