Atomically-thin layers of two-dimensional (2D) materials can be assembled in vertical stacks (called ‘heterostructures’), which are held together by relatively weak van der Waals forces, allowing for coupling between monolayer crystals with arbitrary lattice constants and mutual rotation, or ‘twist’. The twist is a new degree of freedom recently discovered in 2D materials and now widely used in the design of 2D heterostructures. It leads to a new in-plane periodicity in the atomic structure, which changes the optical and electronic properties of the material in profound ways (see for example our recent work in Nature https://www.nature.com/articles/s41586-019-0986-9).
So far, these nanoscale effects could only be probed with standard microscopy tools, providing only spatially-averaged information on a micron scale. Now, with the launch in Sheffield of our state-of-the-art centre for near-field optical spectroscopy, we will achieve 10 nm resolution and absolutely new insights in the physics of 2D materials.
In this PhD project you will apply and develop new pioneering techniques that allow to use light to probe physical processes in a range of semiconductors and nano-photonic devices at the nanoscale with a spatial resolution down to 10 nm.
The PhD project will be based in the newly funded Near-Field Optical Spectroscopy Centre at Sheffield (NOSC) that will start its operation in summer 2021 (see grant award details here: https://gow.epsrc.ukri.org/NGBOViewGrant.aspx?GrantRef=EP/V007696/1).
This is a unique facility (the only one in Europe), where new so-called
‘near-field’ optical methods allowing 10 nm spatial resolution can be applied
in a very wide range of wavelengths from 500 to 15000 nm, therefore opening
possibilities to apply these methods in wide range of science and engineering
disciplines. The methods combine advanced optical techniques with super-high
resolution atomic force microscopy (AFM) (see review covering examples of these
pioneering techniques in
Many collaboration opportunities will exist, as the Centre will be used by a wide range of researchers from physicists, biologists and chemists to materials and biochemical engineers. The Centre will be manned by a Scientific Officer who will closely supervise this PhD, who will also work closely with 2D Materials group led by A Tartakovskii (http://ldsd.group.shef.ac.uk/research/2d-materials/). This PhD student will be supervised by A Tartakovskii an expert in semiconductor physics and photonics.