低温等离子体增强化学气相沉积法制备Ge反opal三维光子晶体及其光学性能

通过溶剂蒸发对流自组装法制备SiO2三维有序胶体晶体模板,采用等离子体增强化学气相沉积法在200℃低温条件下填充高折射率材料Ge,获得了Ge反opal三维光子晶体.实现了低于GeH4热分解温度的低温填充.通过扫描电镜、X射线衍射仪和傅里叶变换显微红外光谱仪对Ge反opal的形貌、成分和光学性能进行了表征.结果表明:沉积得到无定型态Ge,退火后形成多晶Ge,Ge在SiO2微球空隙内填充致密均匀.Ge反opal的反射光谱有明显的光学反射峰,表现出光子带隙效应,其带隙中心波长为1650nm和2640nm,测试的光学性能与理论计算基本符合.采用SU-8光刻胶薄膜也进行了Ge沉积,证实了SU-8模板可以耐受这一沉积温度.低温沉积降低了Ge的填充温度,可以直接采用不耐高温的高分子材料作为初始模板,单次复型制备得到多种构型的完全带隙三维光子晶体.

Fabrication of germanium inverse opal three-dimensional photonic crystal by low temperature plasma enhanced chemical vapour deposition techniques and optical properties

By the solvent vaporization convection self-assembly method,silica colloidal crystal template was prepared.At 200℃,using GeH_4 as the precursor gas,plasma enhanced chemical vapour deposition method was then used to fill the high refractive index material germanium,and germanium inverse opal photonic crystal was obtained.At the temperature lower than the temperature of thermal decomposition,GeH_4 filling of germanium is realized.The morphology,composition,and optical property of the resulting samples were characterized by scanning electron microscopy,X-ray diffraction and Fourier transform microscopic IR spectroscopy.Results show that of germanium is amorphous,it is transformed into polycrystalline state by annealing.The germanium is homogeneously distributed inside the voids of silica template.The reflective spectrum of the sample has remarkable optical reflective peaks and shows the photonic band gap effects.The center wavelength of the photonie band gap lies in 1650nm and 2640nm.There is good agreement between the measured spectra and the calculated band structure.Germanium was also deposited on the SU-8 film,this shows that the SU-8 photoresist can with stand the deposition temperature.Low temperature deposition method decreases the deposition temperature.So this method can use macromolecule materials as templates.Thus the three-dimensional photonic crystal with more kinds of structure can be obtained by single-inversion procedure.