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Moon Sung Kang

Seoul National University, Korea; 2006
B.S. Chemical and Biological Engineering

Email: mskang@umn.edu

Research: Electrical Properties of Semiconductor Nanocrystal Assemblies in Thin-Film Transistors

Semiconductor nanocrystals (NCs) are extremely small pieces of semiconductor material with dimensions in the nanometer (= 10^-9 m) range. Because of their small dimension, the physical and electronic properties are strongly dependent on size. As a result, one can prepare NCs of the same material that emit or absorb different colors of light simply by varying the size of crystal. These size-tunable optical properties of NCs have drawn significant interest for their application in several next-generation electronic devices, in particular light emitting diodes (LEDs) and solar cells. With all the excitement surrounding the potential use of NCs, however, successful incorporation of these materials into practical applications is challenging since assemblies of NCs are not highly conductive for electrical current. This is because individual NCs are coated with insulating molecules, which are necessary to retain the stability of NCs but unfortunately suppress electrical conduction from one NC to another. Also, compared to the well-established work on their optical properties, the electrical properties of NC assemblies have just begun to emerge. To realize the potential of NCs, my research aims to develop methods of obtaining highly conductive NC assemblies, to improve the understanding of their electrical properties, and ultimately to design a new type of NC-based light-emission device.

Publications

"Size-Dependent Electrical Transport in CdSe Nanocrystal Thin Films," M. S. Kang, A. Sahu, D. J. Norris, and C. D. Frisbie, Nano Lett. 2010, accepted

"Thermally Degradable Ligands for Nanocrystals," A. W. Wills, M. S. Kang, A. Khare, W. L. Gladfelter, and D. J. Norris, ACS Nano 2010, 4, 4523-4530

"Influence of Atmospheric Gases on the Electrical Properties of PbSe Quantum-Dot Films," K. S. Leschkies, M. S. Kang, E. S. Aydil, and D. J. Norris, J. Phys. Chem. C 2010, 114, 9988-9996

"High Carrier Densities Achieved at Low Voltages in Ambipolar PbSe Nanocrystal Thin-Film Transistors," M. S. Kang, J. Lee, D. J. Norris, and C. D. Frisbie, Nano Lett. 2009, 9, 3848-3852

"Solar Cells Based on Junctions between Colloidal PbSe Nanocrystals and Thin ZnO Films," K. S. Leschkies, T. J. Beatty, M. S. Kang, D. J. Norris, and E. S. Aydil, ACS Nano 2009, 3, 3638-3648