Preparation and characterization of Ge/TiO_2//Si/SiO_2 one-dimensional heterostructure photonic crystal with infrared spectrally selective low emissivity

摘要

Ge/TiO2//Si/SiO2 one-dimensional heterostructure photonic crystal (1DHPC) was successfully designed and prepared by alternating deposition Ge, TiO2, Si and SiO2 on the quartz substrate via the high vacuum electron beam coating technology. The composition structure and spectral emissivity of the as-prepared 1DHPC were characterized via the scanning electron microscopy (SEM) and fourier transform infrared spectrometer (FTIR), respectively. The microstructure measure result shows that the as-prepared 1DHPC has obvious multilayer structural characteristics, and the thicknesses of Ge layer, TiO2 layer, Si layer and SiO2 layer are basically the same as the design values. The test results of spectral emissivity show that the as-prepared 1DHPC has low infrared emissivity in the 3-5 mu m and 8-14 mu m bands, the average emissivity can be as low as 0.060 and 0.239, respectively. But in the 5-8 mu m band, the as-prepared 1DHPC has higher infrared emissivity (0.562). The results indicate that the as-prepared Ge/TiO2//Si/SiO2 1DHPC has obviously infrared spectrally selective low emissivity characteristic, basically meets the requirements of our design. The results of this paper show that low infrared emissivity materials can still be prepared by using non-infrared transparent materials through a reasonable one-dimensional photonic structural design.