Warwick-led research optimises electronic heterostructures

Two-dimensional materials are flat, atomically thin, highly conductive, and extremely strong. When stacked together they form heterostructures that can be used to create highly efficient optoelectronic devices with ultrafast electrical charges, which in turn can be used in nanocircuits. They are also stronger than materials used in traditional circuits.

Now, Warwick University’s Dr Neil Wilson has developed the technique to measure the electronic structures of these stacks for the first time.

To date, heterostructures have been created using different 2D materials, and stacking different combinations of 2D materials creates new materials with new properties.

Dr Wilson’s technique measures the electronic properties of each layer in a stack, allowing researchers to establish the optimal structure for the fastest, most efficient transfer of electrical energy.

The technique is said to use the photoelectric effect to directly measure the momentum of electrons within each layer and shows how this changes when the layers are combined.

According to the University, the ability to understand and quantify how 2D material heterostructures work - and to create optimal semiconductor structures - paves the way for the development of highly efficient nanocircuitry, and smaller, flexible, more wearable gadgets.

Solar power could also benefit significantly with heterostructures, as the atomically thin layers allow for strong absorption and efficient power conversion with a minimal amount of photovoltaic material.

“It is extremely exciting to be able to see, for the first time, how interactions between atomically thin layers change their electronic structure,” said Dr Wilson. “This work also demonstrates the importance of an international approach to research; we would not have been able to achieve this outcome without our colleagues in the USA and Italy.”

Dr Wilson formulated the technique in collaboration with colleagues in the theory groups at the University of Warwick and University of Cambridge, at the University of Washington in Seattle, and the Elettra Light Source, near Trieste in Italy.

Understanding how interactions between the atomic layers change their electronic structure required the help of computational models developed by Dr Nick Hine, also from Warwick’s Department of Physics.

A paper describing their work - Determination of band offsets, hybridization, and exciton binding in 2D semiconductor heterostructures - is published in Science Advances.