Research Areas

Controlled Synthesis |  Functional Devices for Nanoelectronics | Discovery of Novel Properties |  Nano-Bio Interface

Controlled Synthesis

       Our objective is to develop general chemical approaches to synthesize new nanowires and nanowire heterostructures, of which chemical, physical and structural properties are well controlled.
         A general strategy for synthesizing nanowires involves exploiting a nanocluster ‘catalyst’ to confine growth in 1 dimension. The nanocluster or nanodroplet serves as the site that directs preferential addition of reactant to the end of a growing nanowires. Several specific methods based on this underlying strategy have been developed for the synthesis of nanowires, including metal organic chemical vapor deposition, metal organic vapor-phase epitaxy, laser ablation, chemical vapor deposition and physical evaporation.
       Heterostructures in which the composition and/or doping are varied on the nanometer scale represent equally important—if not more significant—targets of synthesis since they could enable new and unique functions or properties for integration in functional nanosystems. The elaboration of basic homogenous structure to form radial and axial heterostructures can be achieved as follows. Radial growth of a shell of distinct material can be preferred by altering the synthetic conditions to favor homogenous vapor-phase coating on the nanowire surface. On the other hand, an axial heterostructure is prepared by varying the reactant and/or dopant species while maintaining conditions for axial growth. Subsequent introduction of different reactants and/or dopants produces structures of arbitrary composition and doping, leading to great versatility of NWs structures.
        Currently we are exploring controlled synthesis of IV group and III-V nanowires (funded by NSF CAREER) and heterostructures (funded by ARO) using chemical vapor deposition and physical evaporation methods  We are also working on laser-guided growth through collaboration with Xu Group in ME department at Purdue (funded by DARPA).  


Functional devices for Nanoelectronics

       Our objective is to design and develop novel nanoelectronics devices based on new nanomaterials. These devices leverage the well-defined electrical properties at nano scale enabled by controlled synthesis in the homogenous or heterogeneous structures. Representative examples illustrating our approaches included addressing decoders based on modulated doped nanowires (Science, 310, 1304-1307) and single nanowire photodetector (Nano letter 6, 2929-2934 ).
        We are currently working on nanoelectronic devices based on heterostructures and actively collaborating with Appenzeller group and Janes group in ECE at Purdue (funded by NSF GOALI). Purdue Birck Nanotechnology Center ( hosts nanofabrication facilities required by our projects. 


Discovery of Novel properties

     Our objective is to investigate the new fundamental properties of nanostructures, especially new nanomaterials developed by controlled synthesis. We are particularly interested in electrical properties in quantum regime and optical properties. Understanding these fundamental properties will establish a solid ground for us to design and demonstrate new application of nanomaterials in electronics, optics and biology. 


Nano-Bio Interface

      Interfacing nanotechnology with biology has shown great promise for imaging and treatment of diseases. However, the translation of nanomedicine to clinical setting has been slowed down due to limited fundamental understanding of the interactions between nanomaterials and cells. To establish this fundamental understanding and thus enable rational design of nanomedicine, we aim at understanding the role of nanostructure in regulating cellular activities as well as evaluating the potential of bio-conjugated nanostructures in therapeutic applications.















Purdue Chemistry

Purdue Physics

Birck Center