The morphology and optical response of Au and Agnanoparticles capped with dielectric amorphous Si3N4,BN, and Al2O3 layers are studied. Quantitative analysisof high-angle annular dark-field images obtained in a scanningtransmission electron microscope and simulations of opticaltransmittance spectra are used to investigate the dependence ofthe morphology of the nanoparticles on the particle size and onthe capping material. It is demonstrated that capping-layereffects induce a size-dependent and cap-dependent reshaping of thenanoparticles.
