Metal and Alloyed Nanoparticles
Use of metal particles for nanowire growth has strong potential in the future of nanoscale device fabrication. This technique of nanowire fabrication is the process of using a nanoscale metal particle deposited on a substrate to act as a "seed" for nanowire growth. When the seed is exposed to favorable environmental conditions (specific gas, temperature, process steps, etc), the seed becomes the catalyst for the development of nanowires. This has led to the fabrication of group IV nanowires (Silicon, Germanium [6,7], group III-V nanowires (GaAs, InAs) [2-4], and even group II-VI (ZnO)  using such particles.
Utilizing such particle-grown nanowires for nanoscale devices has many advantages. The physical properties of particle-grown nanowires exhibit oriented growth direction and even can be grown in selective areas by controlling where the seed is deposited . Multiple studies have also shown that the metal particle will "ride" atop the developing nanowire and virtually none of the particle is diffused into the nanowire during the growth process . This is important in the future of passing electrons through nanowires as metals can have serious impact on how these devices ultimately will function .
Tohoku University of Japan and UC Davis, in collaboration with a few private companies in Japan and the United States , are currently conducting a survey on the "Research and development activities of metal and alloyed nanoparticle based technologies in Japan and USA " under the international research grant sponsored by New Energy and Industrial Technology Development Organization (NEDO). This survey will work towards identifying existing issues, possible challenges, and future directions for the research of metal nanoparticles. We believe that in the cases of metal nanoparticles the main challenges ahead can be identified as:
(a) The development/identification of the synthesis techniques for the preparation of highly crystalline nanoparticles.
(b) Known issues and ultimately prevention of the surface oxidation of metal nanoparticles.
(c) Identifying new biological and engineering applications for such nanoparticles.
Such research will directly fuel the interests of utilizing new nanoparticles for catalyst-grown structures.
Our research goal is to develop new novel techniques for developing single-crystalline nano-particles for nanowire growth and controlling deposition of such particles to act as seeds for selective growth locations. Of important interest to our studies are those techniques that have been already used to produce metal particles and the contents of the nanoparticles survey. We will be collaborating with Tohoku University in this research project.
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