Elaboration and study of optical properties of CdSe nanocrystals dispersed in a KBr monocrystalline crystalline matrix and in a thin film of SiO2 amorphous matrix

摘要

In this work, we firstly present the elaboration of CdSe nanocrystals (NCs) dispersed in a KBr crystalline matrix in order to build nanostructured composed materials showing monocrystalline structure, and also using another technique, to deposit thin film of amorphous silica (SiO2) containing CdSe quantum dots. These elaborated guest-host systems were investigated for potential applications in optoelectronic field. In the second part of this work, we present the structural and optical properties of these composite materials using several techniques: X-ray-diffraction (XRD), UV-visible absorption. Crystallites size estimated from XRD is equal 27 nm. Optical absorption shows size quantization effect marked by a blue shift by 0.308 eV from its standard bulk band gap value 1.7 eV. Comparing size determined by XRD crystallites size estimated from the blue shift was found to be smaller.