title: Multilayer Black Phosphorus as a Versatile Mid-Infrared Electro-optic Material.
abstract: We investigate the electro-optic properties of black phosphorus (BP) thin films for optical modulation in the mid-infrared frequencies. Our calculation indicates that an applied out-of-plane electric field may lead to red-, blue-, or bidirectional shift in BP's absorption edge. This is due to the interplay between the field-induced quantum-confined Franz-Keldysh effect and the Pauli-blocked Burstein-Moss shift. The relative contribution of the two electro-absorption mechanisms depends on doping range, operating wavelength, and BP film thickness. For proof-of concept, simple modulator configuration with BP overlaid over a silicon nanowire is studied. Simulation results show that operating BP in the quantum-confined Franz-Keldysh regime can improve the maximal attainable absorption as well as power efficiency compared to its graphene counterpart.
authors.affiliation: The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, ON M5S 3G4, Canada.
authors.forename: Charles
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , 200 Union Street SE, 4-174 Keller Hall, Minneapolis, Minnesota 55455-0170, United States.
authors.forename: Roberto
authors.initials: R
authors.lastname: Grassi
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , 200 Union Street SE, 4-174 Keller Hall, Minneapolis, Minnesota 55455-0170, United States.
authors.forename: Tony
authors.initials: T
authors.lastname: Low
authors.affiliation: The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, ON M5S 3G4, Canada.
authors.forename: Amr S
authors.initials: AS
authors.lastname: Helmy
keywords: Black phosphorus; Burstein−Moss shift; electro-optics; mid-infrared; modulator; quantum-confined Franz-Keldysh effect