Abstract Title: Infrared Devices using Graphene-hexagonal Boron Nitride Layered Heterostructures
Nontechnical description:Infrared devices covering a wavelength range from 6 to 15 microns can play a critical role in many optical technologies such as thermal imaging, night vision and free-space optical communications. The most commonly used material for the access to this infrared window is mercury cadmium telluride. However, the growth of mercury cadmium telluride involves toxic elements and hence is highly challenging. Moreover, it is soft and brittle, leading to difficulties in device fabrication and system integration. In this program, the principle investigator and his team will explore an alternative material system based on layered graphene-hexagonal boron nitride heterostructures for the infrared device applications. They will focus on the interaction of infrared light and the heterostructures and optimize their infrared properties. Furthermore, the team will built infrared devices which can perform infrared light detection functions in the wavelength range from 6 to 15 microns. This program will also train students and postdocs and hence contribute to the nation's workforce needs in optics and semiconductor industries. The program will provide students with unique hands-on research training in a rapidly emerging field, while exposing them to multidisciplinary research approaches. In collaboration with Yale Pathways to Science, this program will also educate pre-college students in New Haven area from diverse backgrounds and ethnicities especially under-represented groups, instilling their interests in science and engineering.
Polaritons are quasiparticles resulting from the coupling of photons with electric dipole-carrying elementary excitations such as plasmons, phonons, or excitons. Here the principle investigator and his team will explore graphene based infrared polaritonic devices covering an important mid-infrared wavelength range from 6 to 15 µm. They will investigate plasmon, phonon, and plasmon-phonon polaritons in large area hybrid structures consisting of graphene and hexagonal born nitride (hBN). The overall goals are to achieve unprecedented light-matter interaction and to realize high performance polaritonic imaging elements in the infrared. The key element of this proposal is the enhanced light-graphene interaction using polaritonic resonances. The principle investigator proposes two complementary thrusts: (1) Understand the plasmon, phonon, and plasmon-phonon polaritons and their damping processes in graphene-hBN heterostructures and build polaritonic photodetectors in mid-infrared (6 to 15 µm) based on lateral nanoribbon junctions; and (2) Understand the hot-carrier dominated thermionic emission effect in vertical heterostructures and build polariton enhanced photodetectors utilizing hot-carrier thermionic emission. The proposed research will lead to new optical devices based on an alternative material system. Systematic study on plasmon, phonon, and plasmon-phonon polaritons including their damping pathways will lead to discoveries of new optical physics in two-dimensional layered materials.
