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本文使用多光束干涉方法构造三维周期性微纳结构.通过多次匀胶与单次曝光结合,在负光刻胶SU8上刻蚀出含平面缺陷的类金刚石结构(fcc-like)光子晶体.扫描电子显微镜(SEM)观测显示,相比无缺陷光子晶体结构,该结构在(111)晶面上存在清晰可见的平面缺陷.通过控制匀胶时的转速,可以精确控制平面缺陷厚度在适合的范围.傅里叶红外反射光谱测试显示完整周期微纳结构在(111)方向上有明显的特征峰,两个特征反射峰中心波长接近1.2μm和2.4μm.含缺陷的结构则在反射光谱特征峰中掺入了明显的凹陷,并且随着平面缺陷的厚度增大,缺陷模从处于2.4μm禁带移至1.2μm禁带处.提取SEM图中的结构参数,用FDTD方法模拟分析,发现模拟结果与实验值基本一致,证明了平面缺陷不但存在,而且面积较大.
In this paper, a multi-beam interference method is used to fabricate a three-dimensional periodic micro / nano structure, and a fcc-like photonic crystal containing plane defects is etched on the negative photoresist SU8 by combining multiple spin-on and single-shot exposures. Scanning electron microscopy (SEM) observations show that the structure has clearly visible planar defects on the (111) crystal plane compared to the defect-free photonic crystal structure. By controlling the spin speed during spin down, the thickness of the planar defect can be precisely controlled Range.The Fourier transform infrared spectroscopy (FTIR) spectroscopy showed that the complete periodic micro / nano structure has obvious characteristic peaks in the (111) direction, and the center wavelengths of the two characteristic reflection peaks are close to 1.2μm and 2.4μm.The structures with defects are characterized by reflectance spectra The peak is doped with obvious depressions, and as the thickness of the planar defect increases, the defect mode shifts from the forbidden band of 2.4μm to the band gap of 1.2μm.The structural parameters in the SEM image are extracted, and the FDTD method is used to simulate the analysis. The simulation results are basically the same as the experimental ones, which proves that plane defects not only exist, but also have larger area.