Low-Temperature Scanning Tunnelling Microscopy

Scanning tunnelling microscopy (STM) is the only experimental technique which uniquely combines atomic-resolution imaging of materials' surfaces with the ability to manipulate matter at the atomic-scale. We use low-temperature (LT-STM) in ultra-high vacuum to study the atomic and electronic structure of two-dimensional (2D) and topological materials, and combine these with atomic-precision atomic manipulation and lithography schemes.



Low-temperature STM allows to resolved the atomic and electronic structure of atomically thin two-dimensional (2D) electronic materials such as graphene and the transition metal dichalcogenides (TMDCs) MoS2, WS2, MoSe2, .. etc. Scanning tunnelling spectroscopy (LT-STS) allows to access some of the materials' electronic properties such as local doping and band structure. A topographic image of a graphene monolayer transferred to a sapphire substrate is shown on the right. The inserts show the surface morphology/roughness arising from the substrates, and the characteristic hexagonal carbon lattice, respectively



Interactions of the STM's probe tip and the sample's surface allows for atomic manipulations and lithography. Ultimately, this can allow for the construction of atomic-scale electronic devices and device architectures which can be studied, not only by STM but also in electron transport. The image on right shows a few-atom double quantum dot (DQD) device with source (S) and drain (D) leads, lithographically defined by STM lithography on the hydrogen terminated surface of a silicon substrate. Read more here