Interlayer exciton transport devices using 2D semiconductor heterostructures

The overarching objective for this project is to realize novel optical and electronic devices using unprecedented spatial control of interlayer exciton (IX) flow and quantum tunneling in two-dimensional (2D) semiconductor heterostructures. An IX is a bound object consisting of an electron and hole that are spatially localized to different layers. Over the past decade, there has been significant interest in controlling IXs for future optical and quantum device applications.

The project will develop unprecedented spatial control of IXs for potential applications to high speed and low power consumption optoelectronic devices. Based on the increasing need of computing power and the associated energy demands, the development of novel information processing devices that harness quantum effects at higher temperatures is critical.

In addition, this project will train graduate, undergraduate and high school students in the area of nanoscale semiconductor devices which have the potential for revolutionary advancements in quantum information systems. The education and outreach activities focus on promoting the STEM fields by directly recruiting, providing research opportunities and career mentorship for high school students and UA undergraduates working with the University of Arizona’s Arizona Science, Engineering, and Mathematics Scholars Program, and KEYS program.

The proposed project to spatially control IXs is at the state-of-the-art of 2D material device design, fabrication, and applications. The ability to trap IXs at the nanoscale was only recently developed by the PIs’ groups. Building on these recent developments, we will fabricate and optically investigate bilayer semiconducting transition metal dichalcogenide heterostructures with nano-patterned graphene top gates to generate custom potential-energy landscapes to realize unprecedented spatial control of IX flow and tunneling.

Very recently, our team has reported evidence of high temperature IX superfluidity, motivating new devices that utilize this quantum phase. The project has two specific research aims: 1) demonstrate spatial control of valley-polarized IX flow, 2) demonstrate IX tunneling across a potential barrier and the equivalent of the Josephson effect in IX superfluid structures.

Controlling of IXs will include both the demonstration of a valley-polarization based IX transistor as well as a valley-based filter that makes use of the valley Hall effect. IX currents will enable applications in low energy consumption valleytronic material devices. We will demonstrate the first ever 2D semiconductor based IX tunneling devices based on two IX traps separated by a tunneling barrier.

The final goal of this research is to demonstrate Josephson-like IX oscillations which have potential applications in quantum technology devices such as on chip interferometers and gyroscopes.

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.