Abstract: ZnS photonic crystals were prepared by using silica collodial crystals as templates and infiltrating with ZnS semiconductor nanocrystals in opal templates via solvothermal approach. Solvothermal method offers several advantages over previous techniques including homogenous ZnS growth within the opal voids and high quality of the obtained ZnS nanocrystals. XRD patterns and Raman spectroscopy results confirmed the ZnS nanocrystals to be zinc blende, and the mechanism of ZnS crystal growth in opals was discussed. FESEM images and UV-Vis transmission spectra showed that the as-obtained ZnS/opal system and ZnS inverse opal kept the three-dimensional ordered structure of the opals. The appearance of Bragg diffraction peak at Г-L direction (the direction normal to the (111) planes) indicated that the two structures had excellent photonic crystals properties. Furthermore, the optical properties of the infiltrated opals with different ZnS filling ratios are also studied by transmission spectroscopy. It is proposed that the position of the stop band can be easily designed by controlling the infiltration ratio of ZnS. These results demonstrated an easy-to-handle and efficient route to obtain high performance photonic crystal structures. The material system is believed to have potential applications in optoelectronic and photonic devices.

Key words: Photonic crystals, Solvothermal, Self-assembly, ZnS, Opal