(4dy) Atom-by-Atom Metrology of Materials for Microelectronics, Energy and Biology

My research efforts focus on clarifying the fundamental mechanisms governing the synthesis of size-, shape- and composition-controlled nanoscaled systems for information storage nanoelectronics, energy sciences and biology. Metallic and semiconductor inorganic nanostructures hold an array of unique magnetic, electronic and photonic behavior that often differs from their bulk counterparts. The overarching goal of the research proposed herein is elucidating the synthesis-structure-performance relations of atomic-scaled materials by advanced microcharacterization techniques to engineer properties such as tunneling magnetoresistance (TMR), photovoltaic conversion, energy storage and catalytic activity. Nanofabrication techniques are pursued for nanoelectronics applications involving the demonstration of memory spin-based devices that are scalable to their ultimate physical limits. Diverse routes undertaken to fabricate spin-transfer-torque random access memories (STT RAM) are presented. Monolayer assemblies of FePt nanostructures have been fabricated with different geometries, including nanorods, oval-shaped particles and spherical particles for rational control of their magnetic properties. The employed wet-chemistry technique emerges as a low-cost alternative for fabricating magnetic nanostructures with much smaller dimensions than conceivable with lithographic methods. The coercive field of these FePt nanostructures can be tuned by engineering their shape. Micromagnetic calculations acquired using the code OOMF (Object Oriented MicroMagnetic Framework) explain the enhancement of the coercivity as consequence of geometry elongation in the colloids. Our research group endeavors will also serve to answer critical issues in the design and development of low cost, highly efficient nanomaterials that can ease widespread use of clean energy technologies such as solar cells, electrochemical capacitors and biofuels to address the world's energy and environmental challenges. The students of my research group will be skilled on the fabrication, characterization and application of inorganic nanomaterials to meet the research goals needed to ensure that viable fossil fuel alternatives are developed. The biodistribution of silver nanostructures injected into animals in vivo is currently unknown, remaining as a fundamental issue for potential therapeutic applications. Nanotoxicology efforts will aim at injecting metallic nanocrystals in live rats to elucidate their fate in several organs including liver, heart and brain. Very significant accumulations of nanoparticles were confirmed by inductively coupled plasma mass spectroscopy (ICPMS) and transmission electron microscopy (TEM) techniques on the liver and heart. In contrast, the brain tissue did not reveal evidence of particles content. Our results suggest that Ag+ permeated across the blood?brain barrier (BBB), and followed swift clearance from the organ.