|Paul David Cunningham
The objective of this research effort is to understand the nonequilibrium dynamics of quasiparticles and polaritons in transition metal dicahcogenides (TMDCs) and their heterostructures.
Our work is multidisciplinary. Members of our team fabricate monolayer TMDCs (e.g., WS2, MoSe2, etc.) and other 2D materials (hBN, Graphene) by exfoliation or chemical vapor deposition. Heterostructures and other device geometries are assembled using mechanical transfer techniches. Photonic structures and device conacts are fabricated using lithographic techniques. A wide range of instruments are employed to characterize these materials: photoluminescence mapping, Raman mapping, ellipsometry, etc. Additional instrumentation resides in the Nanoscience Institute, a shared facility open to researchers on our campus.
Our group is interested in the behavior of excitons, trions, and exciton-polaritons in TMDCs. Our research topics include:
- energy and charge dynamics in homo and heterobilayers
- strong coupling, exction polariton dynamics and nonlinear behavoir
- photonic integration, waveguiding and Purcell enhancement
- single photon emission
Our Laser Lab is used to interrogate these systems with a variety of static and time-resolved spectroscopic techniques. Our facility includes angle-resolved transmission/reflection/fluorescence with a closed cycle cryostat, photon correlation measurements via time-correlated single photon counting (TCSPC) with a closed cycle cryostat, femptosecond transient absorption spectroscopy in the UV/VIS and NIR, time-resolved photoluminescence via TCSPC with detectors spanning the visible and near-infrared regions, cryostats compatible with time-resolved setups, etc.
Qualified candidates should possess or be completing a PhD in physics, chemistry, or related discipline with experience in time-resolved spectroscopy. Ultrafast spectroscopy or time-resolved microscopy are a plus, as is familiarity with photophysics in either two-dimensional transition metal dichalcogenides, other low dimensional semiconductors, organic semiconductors, or other excitonic systems.
Cunningham, et al., J. Phys. Chem. Lett. 7, 5242 (2016) – Exciton-Exciton Annihilation
Cunningham, et al., ACS Nano 11, 12601 (2017) – Bandgap Renormalization
Cunningham, et al., Nat. Commun. 10, 5539 (2019) – Valley Optical Stark Effect
Photophysics; 2D materials; Transition metal dichalcogenides; van der Waals, cavities; polaritons; Spectroscopy; Time-Resolved