One-Step Synthesis and Electrical Conductivity of CdSe-Based Nanocomposites

We have developed novel hydrothermal (HT) and hydrothermal microwave (HTMW) processes for the synthesis of nanocrystalline cadmium selenide via reduction using glucose and sodium sulfite. The materials thus obtained have been characterized by X-ray diffraction, CHNS analysis, and electron microscopy. The results demonstrate that they crystallize with a cubic and/or hexagonal symmetry and are nanocomposites containing 14 to 60 wt % organics. Varying synthesis conditions (temperature, composition of the starting mixture, and reaction time) allows one to obtain samples with sizes of coherent scattering regions from 6 to 80 nm. The use of the HTMW process reduces the synthesis time to 15 min in comparison with HT synthesis. The electrical resistance of nanocomposites, measured by the microwave loss method is 10–4 to 10–3 Ω cm, which is considerably lower than the resistivity of corresponding CdSe crystals. The data obtained in this work can be accounted for by the presence of carbon-containing components of the composite, which constitute a shell of particles. The increase in the cross-sectional area of “carbon channels” with decreasing nanoparticle size leads to an increase in the electrical conductivity of the material.