Microstructural study of CdS/opal composites

CdS/opal photonic materials have been characterised by transmission electro n microscopy. The photonic properties of opals formed by SiO2 nanospheres 3 80 nm in diameter, face-centred cubic ordered and with different CdS fillin g factors were studied by means of specular reflectance or transmission spe ctroscopy. It is shown that CdS semiconductor grows homogeneously in the op al interstices, in a cubic phase, with 24 nm being the microcrystal particl e 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 g ap materials. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.