Metallic Alloy Nanoparticles and Metal-Semiconductor Nanomaterials

Abstract

While bridging the gap between the atomic structures and bulk matters, nanomaterials are of great interests for fundamental understanding as well as for different application perspectives. In this article, it is proposed to provide a review regarding various synthesis processes of nanomaterials, growth mechanisms and a range of experimental techniques to discuss remarkable properties of materials at the nanoscale dimensions. Equilibrium (ambient or vacuum thermal annealing) as well as non-equilibrium (for example, utilizing ion-beams) methods are elaborated for the processing of nanomaterials. Here, nanomaterials stand for species of metal nanoparticles, bimetallic alloy nanoparticles or composite materials of metal nanoparticles in different oxide semiconductors. Akin to the pure metal nanoparticles, alloy metal nanoparticles exhibit exciting optical responses. For example, surface-plasmon resonance frequencies of bimetallic alloy nanoparticles are tunable in controlled fashions through the variation of alloy compositions. Metal nanoparticles in semiconductors are discussed to elucidate examples of quasi-particle interactions between plasmons and excitons in the composite as well as interesting photoluminescence properties of the nanomaterials. Thermal stability of semiconductors and growth of the nanoscale metal particles in the composites are found to play crucial roles in this regard. Depending on the growth of metal nanoparticles, for instance, photoluminescence intensity of semiconductors is observed to be enhanced or quenched in the metalsemiconductor composite nanostructures.