Event Description
Paola Barbara, PhD, Georgetown University
Optoelectronics with Atomically Thin Materials: The Good, the Bad and the Unexpected
Materials that are one or a few atomic layers thick make it possible to experimentally study quantum confinement in two, one and zero dimensions. Beyond their exciting physics, these materials show great promise for applications, especially for ultra-thin electronics on flexible substrates. Their direct bandgap (for monolayer semiconducting transition metal dichalcogenides) and their considerable light absorption also make them ideal candidates for very sensitive photodetection. I will discuss the light detection mechanism of two different types of devices based on two different materials, semiconducting monolayer molybdenum disulfide [1,2] and gapless monolayer graphene [3-5]. These two examples will highlight the challenges, opportunities and counterintuitive physics that arise when working with materials where almost all the atoms are on the surface.
[1] P. Han, L. St Marie, Q. X. Wang, N. Quirk, A. El Fatimy, M. Ishigami, P. Barbara, Highly sensitive MoS2 photodetectors with graphene contacts. Nanotechnology 2018, 29 (20).
[2] P. Han, E. Adler, Y. Liu, L. St. Marie, A. El Fatimy†, S. Melis, E. Van Keuren and P. Barbara, Ambient Effects on Photogating in MoS2 Photodetectors, submitted.
[3] A. El Fatimy, R. L. Myers-Ward, A. K. Boyd, K. M. Daniels, D. K. Gaskill, P. Barbara, Epitaxial graphene quantum dots for high-performance terahertz bolometers. Nature Nanotechnology 2016, 11 (4), 335-+.
[4] A. El Fatimy, A. Nath, B. D. Kong, A. K. Boyd, R. L. Myers-Ward, K. M. Daniels, M. M. Jadidi, T. E. Murphy, D. K. Gaskill, P. Barbara, Ultra-broadband photodetectors based on epitaxial graphene quantum dots. Nanophotonics 2018, 7 (4), 735-740.
[5] A. El Fatimy, P. Han, N. Quirk, L. St. Marie, M. T. Dejarld, R. L. Myers-Ward, K. Daniels, S. Pavunny, D. K. Gaskill, Yigit Aytac, T. E. Murphy and P. Barbara, Measurements of defect-induced cooling in graphene hot-electron bolometers, submitted. |
