We believe our paper caught the interest of the scientific community due to the fact that we present a novel form of a class of materials showing important properties of long-term interest as well as demonstrating their potential to be used as functional building blocks for nanoscale devices in a simple manner.

“The fun of purely scientific exploration and the reward of making practical applications possible with this new class of materials has just begun.”

Noble metal nanoparticles encapsulated in dielectric matrices have attracted a sustaining interest over a few centuries due to their novel optical and electrical properties. A classic example of this type of material is colored glass, used even long before the "Nano Era." During the last few decades, such metal-dielectric nanocomposites were considered to be useful for optical switching device applications owing to their nonlinear and fast optical response near the surface plasmon resonance (SPR) frequency.

Previously, all these nanocomposites were mainly prepared in thin film or bulk forms. Nanowire has only very recently become a rapidly growing research field. Our Au nanoparticles-embedded dielectric nanowires exhibiting color-selective sensitivity is thus of interest, at least for the enormous number of researchers in both the metal-dielectric composites and nanowires communities.

The effect of SPR on photoconductivity is a new discovery and the micro-reactor technique we have developed is also a new methodology. We have demonstrated for the first time a strong wavelength-dependent and reversible photoresponse in a two-terminal device using an ensemble of Au nanopeapodded silica nanowires under light illumination, while no photoresponse was observed for the plain silica nanowires.

By adjusting the process parameters, we can obtain Au nanorods with different aspect ratios, which result in SPR peak shift, thus allowing switching with tunable color selectivity. The process we have described to form the dielectric-based hollow tubular nanostructure, followed by filling metal core and subsequent transforming to a chain of nanospheres or nanorods, in a self-organized manner, has not been reported before.

We provide a platform technology for synthesizing a complex structure, yet without process complexity. It is also fascinating how such a simple technique can produce novel structures that can further be applied toward nanodevices. This is what innovation is about.

The core competence of my lab has been in utilizing various thin-film techniques, in particular chemical vapor deposition and physical vapor deposition, to develop functional advanced materials, in various morphological forms, ranging from near single-crystal, and epitaxial film to nano-structures.

Most of these techniques involve synthesizing materials in conditions far away from an equilibrium process; therefore offering an unprecedented opportunity for forming metastable phases and novel structures that can not be produced by conventional techniques. Carbon nanotube (CNT) is a well known case. We started our research on CNTs in the mid ’90s. Later on, it became quite obvious that nanowires are as interesting and important as CNTs.

I am quite pleased that our earlier papers on GaN and ZnO nanowires have also been highly cited. Certainly there were, and still are, problems or challenges, the main ones being the precision control in their dimension, length scale, and orientation, as well as producing structures as initially designed. Nevertheless, there are pleasant surprises, which often become a blessing in disguise.

Our approach could also be extended to preparing a wide range of metal/dielectric peapod-type nanowires. Such a hybrid system with a variety of functionalities forms a new class of materials, which offer great opportunities for innovated applications, unmatched by their thin-film or bulk counterparts. The fun of purely scientific exploration and the reward of making practical applications possible with this new class of materials has just begun.

Many nanomaterials, and/or the processes to produce them, are of societal concerns due to their potential threat to our health and environment. The process we’ve developed is efficient and environmentally benign.