Collaborative Research: Tellurene mid-infrared integrated photonics

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Lack of optical materials compatible with common semiconductor substrates presents a standing hurdle for integrated photonic device development in the mid-IR domain. This award supports a collaborative team to conduct fundamental research to advance knowledge for the integration of emerging optical nanomaterials with the mid-IR photonics platform. The research aims to enable the design, fabrication, and integration of mid-IR photonic components and circuits based on a new optical nanomaterial, namely two-dimensional (2-D) tellurene. Tellurene, atomically thin crystals of elemental tellurium, is an emerging 2-D material amenable to scalable synthesis and uniquely combines small and tunable bandgap energies, high carrier mobility, exceptionally large electro-optic activity, and superior chemical stability, which makes it a promising and versatile material platform for mid-IR photonics. The mid-IR spectral band (2-20 micro-meter) is of significant technological importance for thermal imaging, spectroscopic sensing, infrared countermeasures, and free-space communications. The proposed tellurene-based device platform, once demonstrated, will have a transformative impact on mid-IR integrated photonics. The envisioned detector and modulator devices both are predicted to have performances far exceeding the state-of-the-art. This research involves several disciplines, including materials science, electrical engineering, photonics, device physics, manufacturing, and chemistry. The multi-disciplinary research combined with the proposed outreach activities will provide valuable opportunities for exposing the students to cutting-edge nanotechnology and optical sciences to inspire their interest in STEM career paths.2-D materials have emerged as a promising material group for photonic integration, given their singular optical properties not found in conventional bulk and thin-film materials. However, some scientific and technical barriers are yet to be overcome to realize the full application potential of 2-D materials for mid-IR integrated photonics. This research is to fill the knowledge gap on the integration of solution-synthesized tellurene with the mid-IR photonics platform. The objectives are (1) to demonstrate high-performance waveguide integrated room-temperature mid-IR photodetectors and ultrafast electro-optic modulators based on tellurene, and (2) to explore the unique advantage and capability of solution-synthesized tellurene as a novel optical material for integrated mid-IR photonic devices. The research team will innovate a processing scheme that directly fabricates waveguide structures on tellurene using compositionally-engineered chalcogenide glass as both the light guiding medium and an infrared-transparent gate dielectric. This monolithic approach capitalizes on the broadband mid-IR transparency and near-room-temperature processing of chalcogenide glass to not only simplify the integration process but also allow the photonic circuit to be specifically optimized and precisely aligned to tellurene crystals with lithographic accuracy. The team will also develop a physics-based framework to design and guide the material synthesis, device fabrication, and system integration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.