Electro- and Photoluminescence of CdS Nanoparticles Deposited on Carbon Nanotubes

Array of aligned carbon nanotubes (CNTs), vertically grown on conductive silicon substrate, has been used for deposition of CdS nanoparticles in a chemical bath. Luminescent properties of the nanoparticles were studied with applying the voltage to the silicon substrate or irradiating the CdS/CNT hybrid by ultraviolet light. It is found that electroluminescence has the green color characteristic for bulk CdS, while photoluminescence corresponds to the blue spectrum of quantum dots with an average size of similar to 1.53 nm. From high-resolution transmission electron microscopy examination, the observed spectral difference is attributed to different size of CdS nanocrystals grown on the surface and in the interior of the array.