Associate Professor of Electrical and Computer EngineeringDr. 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, where she investigated high-temperature quantum dot infrared photodetectors grown by molecular beam epitaxy. Dr. Stiff-Roberts joined Duke University in August 2004, and she is currently an Associate Professor.
Dr. Stiff-Roberts' research interests include the synthesis of multi-component and hybrid (organic-inorganic) materials using a novel approach for organic-based thin film deposition that combines solution and vacuum-processing. Known as emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE), this technique offers a completely new way to integrate novel functions into organic-based films and devices that are difficult, if not impossible, to achieve otherwise. Research efforts include materials synthesis and characterization to investigate the fundamental mechanisms of thin-film growth using RIR-MAPLE, as well as device fabrication and characterization for a broad range of applications (especially optoelectronic and energy devices).
Appointments and Affiliations
- Associate Professor of Electrical and Computer Engineering
- Faculty Network Member of The Energy Initiative
- Office Phone: (919) 660-5560
- Email Address: firstname.lastname@example.org
- Ph.D. University of Michigan at Ann Arbor, 2004
- M.Sc.Eng. University of Michigan at Ann Arbor, 2001
- B.S.E.E. Georgia Institute of Technology, 1999
- B.S. Spelman College, 1999
Nanomaterials resulting from quantum confinement in three dimensions, known as nanoparticles or quantum dots, exhibit unique characteristics compared to conventional, bulk materials because of their small size, and because nanomaterials can be tailored to exhibit desired properties by controlling their synthesis and their incorporation into thin films. My research group investigates two different types of quantum dots. First, epitaxial quantum dots (EQDs) are inorganic, compound semiconductor nanomaterials synthesized in ultra-high vacuum, crystal growth systems, such as molecular beam epitaxy (MBE). These nanostructures are three-dimensional islands with a lens or pyramid shape that are affixed to a substrate and result from strained-layer epitaxy, which occurs due to the lattice mismatch between the EQD material and a surrounding compound semiconductor material (matrix). Second, colloidal quantum dots (CQDs) are dielectric, semiconductor, or metallic nanomaterials synthesized by inorganic chemistry and surrounded by organic molecules such that they are soluble. These nanostructures often have a spherical shape and are frequently embedded in an organic matrix material, such as charge conducting polymers. These material systems are then called organic/inorganic hybrid nanocomposites. Hybrid nanocomposites are especially interesting because they could enable a new class of optoelectronic devices that are low-cost, can be deployed in novel ways, and can provide multiple functions for unique applications. For example, the simultaneous detection of light across different wavelength regions, or multi-spectral photodetection, could be achieved by integrating different CQDs in a single device. An important challenge to making useful devices from hybrid nanocomposites is controlling the synthesis of thin films. A novel component of my research is a hybrid nanocomposite thin film deposition technique known as matrix-assisted pulsed laser evaporation (MAPLE). My group has established a new approach to MAPLE deposition that drastically expands its applicability to numerous material systems and yields thin films with structural properties comparable to the best achieved using traditional solution-based techniques.An important aspect of my work is to demonstrate the value added by MAPLE in terms of electrical and optical properties of hybrid nanocomposite thin films, as well as enhanced device performance and unique device structures that can be achieved.
Awards, Honors, and Distinctions
- IEEE Early Career Award in Nanotechnology for “contributions to the development of nanoscale quantum dots for infrared detection”. IEEE Nanotechnology Council. 2009
- Senior Member. IEEE. 2009
- Presidential Early Career Award for Scientists and Engineers. Department of Defense, Office of Naval Research. 2008
- Young Investigator Award. Office of Naval Research. 2007
- NSF CAREER AWARD. National Science Foundation. 2006
- Inducted. Phi Beta Kappa Society. 1998
- Inducted. Sigma Pi Sigma Physics Honor Society. 1998
- Inducted. Golden Key Honor Society. 1996
- ECE 230L: Introduction to Microelectronic Devices and Circuits
- ECE 340L: Optics and Photonics
- ECE 521: Quantum Mechanics
- Ge, W; Atewologun, A; Stiff-Roberts, AD, Hybrid nanocomposite thin films deposited by emulsion-based resonant infrared matrix-assisted pulsed laser evaporation for photovoltaic applications, Organic Electronics, vol 22 (2015), pp. 98-107 [10.1016/j.orgel.2015.03.043] [abs].
- Yu, Q; Ge, W; Atewologun, A; Stiff-Roberts, AD; López, GP, Antimicrobial and bacteria-releasing multifunctional surfaces: oligo (p-phenylene-ethynylene)/poly (N-isopropylacrylamide) films deposited by RIR-MAPLE., Colloids and Surfaces B: Biointerfaces, vol 126 (2015), pp. 328-334 [abs].
- Stiff-Roberts, AD; McCormick, RD; Ge, W, Material properties and applications of blended organic thin films with nanoscale domains deposited by RIR-MAPLE, Proceedings of SPIE - The International Society for Optical Engineering, vol 9350 (2015) [10.1117/12.2079858] [abs].
- Ge, W; Nyikayaramba, G; Stiff-Roberts, AD, Bulk heterojunction PCPDTBT:PC71BM organic solar cells deposited by emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation, Applied Physics Letters, vol 104 no. 22 (2014), pp. 223901-223901 [10.1063/1.4881058] [abs].
- Ge, W; Yu, Q; López, GP; Stiff-Roberts, AD, Antimicrobial oligo(p-phenylene-ethynylene) film deposited by resonant infrared matrix-assisted pulsed laser evaporation, Colloids and Surfaces B: Biointerfaces, vol 116 (2014), pp. 786-792 [10.1016/j.colsurfb.2014.01.033] [abs].