MIOMD-XI Speakers    
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1.  Prof. Adrienne Stiff-Roberts, Duke University, USA
Invited Talk: Hybrid nanocomposite infrared photodetectors
Speaker Biography: Prof. Stiff-Roberts received both the B.S. degree in physics from Spelman College and the B.E.E. degree in electrical engineering from the Georgia Institute of Technology in 1999. She received an M.S.E. in electrical engineering and a Ph.D. in applied physics in 2001 and 2004, respectively, from the University of Michigan, Ann Arbor. As an Associate Professor of Electrical and Computer Engineering at Duke University, her current research interests include thin-film growth and characterization of polymer, nanoparticle, and hybrid nanocomposites; as well as the design, fabrication, and characterization of optoelectronic devices, especially multispectral photodetectors. Dr. Stiff-Roberts is a recipient of the NSF CAREER Award (2006), the ONR Young Investigator Award (2007), the IEEE Early Career Award in Nanotechnology of the Nanotechnology Council (2009), and the Presidential Early Career Award in Science and Engineering (2009).

Summary: An inexpensive, near-room-temperature, multi-spectral infrared (IR) photodetector is desirable for IR imaging and gas sensors. Semiconductor nanoparticles, or colloidal quantum dots (CQDs), are positioned to enable such technology due to the three-dimensional quantum confinement of the active region. In addition, CQDs benefit from: i) the ability to conduct size-filtering, leading to highly-uniform ensembles, ii) a spherical shape that simplifies calculations for device modeling and design, and iii) greater selection of active region materials because strain considerations that dominate the growth of epitaxial quantum dots are eliminated. CQDs are typically coated with short, organic molecules to prevent aggregation in solution. Hybrid nanocomposite thin films comprising CQDs embedded in an organic conducting polymer have demonstrated room-temperature infrared photodetection. In analogy to the InAs/GaAs quantum dot infrared photodetector (QDIP), this work presents a unique approach to achieve unipolar, intraband transitions appropriate for room-temperature, mid- and long-wave-IR photodetection using hybrid nanocomposites. A conducting polymer with a large energy gap serves as the CQD matrix material in order to enhance quantum confinement and electron localization in CQD confined energy levels.
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