Single-Molecule Electronics and Optoelectronics
Electronic and optical devices based on molecules and nanostructures have received considerable attention recently, but the basic process that underlies the function of these devices is still not well understood. Our group is developing experimental methods to incorporate individual molecules and nanostructures into optoelectronic devices and studying their electrical and optical behaviors in detail to gain insights about their behavior.
Oxide and Chalcogenide Nanostructures
Oxides and chalcogenides exhibit a host of thermodynamic, electronic, and magnetic properties that are fascinating yet poorly understood. Examples of these properties include ferroelectricity, high-Tc superconductivity, colossal magnetoresistivity, and crystalline-amorphous phase change. These oxides and chalcogenides also exhibit a variety of electronic, magnetic, and structural fluctuations with varying energy and length scales that are believed to be responsible for many exotic properties of the material. We are synthesizing nanostructures of oxides and chalcogenides and probing their physical chemistry.
Phase Transition of Individual Nanostructures
Phase transitions in finite sized systems have played an important role in the development of the statistical theory of critical phenomena. Corresponding experimental studies, on the other hand, have been rare due to the lack of reliable methods to prepare well-defined clusters. Essentially all the experimental studies to date have been performed on ensembles of nanostructures with differing sizes, and consequently many interesting aspects of finite-size scaling could not be fully tested. We are investigating the phase transitions of individual nanostructures using novel scanning probe techniques.
Neuron-Electronic Interfacing
Neural networks, collections of neurons interconnected by synaptic junctions, form the physical basis of the central and peripheral nervous systems in biological organisms. These networks are responsible not only for the reaction of the organism to external stimuli but also for more highly organized cognitive functions such as memory, learning, and logic. We are interested in deciphering the inner workings of neural networks by coupling biological neural networks to nano- and micro-fabricated nanoelectrode and patch-clamp arrays and by probing real-time dynamics of neural connections using both electrical and optical interrogation. The research efforts should enable the detailed mapping of the action potential propagation and synaptic adaptation within the network, and therefore help answer crucial questions pertaining to biological neural networks.