Abstract:

Monodisperse silica microspheres were assembled into a three-dimensional colloidal crystal template with long-range order by the solvent vaporization convection self-assembly method. Using GeH4 as the precursor gas, the plasma enhanced chemical vapor deposition method was then used to fill the voids of the silica colloidal crystal template with high refractive index germanium, then silica colloidal crystals template was removed by an acid etching. Thus germanium inverse opal photonic crystal was obtained. The modality, components, structure and optic capability of the resulting samples were characterized by scanning electron microscope and X-ray diffraction and Fourier transform microscopic IR spectroscopy. The results show that germanium is homogeneously distributed inside the voids of the silica template. The crystalline state of germanium is polycrystalline state. Germanium inverse opal exhibits a three-dimensional ordered porous structure. The spectrogram of the samples has optic reflective apexes and shows the photonic band gap effects. The complete three-dimensional bandgap lies in mid infrared (about 3.4µm) and experiment optic capability is inosculated with the calculated one.

Key words: germanium inverse opal, photonic crystal, a complete three-dimensional bandgap, plasma enhance chemical vapor deposition, solvent vaporization convection self-assembly, mid infrared