Microstructural study of CdS/opal composites Original Research Article

CdS/opal photonic materials have been characterised by transmission electron microscopy. The photonic properties of opals formed by SiO2 nanospheres 380 nm in diameter, face-centred cubic ordered and with different CdS filling factors were studied by means of specular reflectance or transmission spectroscopy. It is shown that CdS semiconductor grows homogeneously in the opal interstices, in a cubic phase, with 24 nm being the microcrystal particle size. We show here that chemical bath deposition (CBD) is a useful method to fill the opal interstices, a crucial step for producing photonic band gap materials.