Speaker
Description
Controlling the placement and electronic character of dopant atoms in semiconductors lies at the heart of both classical device technology and the emerging field of semiconductor quantum computing. As device dimensions approach the single-atom limit, however, the discrete quantum-mechanical nature of individual dopants demands fundamentally new approaches to fabrication and characterisation. Understanding how a dopant wavefunction is shaped by its host crystal, and how quantum confinement evolves as doped layers approach atomic thickness, are central questions that bridge fundamental defect physics and device engineering.
In this talk, I will present an overview of our group’s recent work on atomic-scale dopant systems in silicon and germanium, combining ultrahigh vacuum scanning tunnelling microscopy (STM), soft X-ray angle-resolved photoemission spectroscopy (SX-ARPES), and theoretical modelling. We explore how dopant species, host material, and fabrication pathways influence incorporation, electronic structure, and quantum confinement. These studies include the development of alternative dopant chemistries enabling high-yield incorporation, the realisation of ultra-confined electronic systems in atomically thin doped layers, and the direct imaging of anisotropic dopant wavefunctions in silicon arising from the interplay of crystal symmetry and quantum confinement [1–5].
Taken together, this work advances atomic-scale control of dopant placement in silicon and germanium, and provides new insight into how atomic-scale structure and chemistry govern the electronic states of dopants and dopant structures in semiconductors.
[1] Schofield et al., Nano Futures 2025, 9, 012001.
[2] Siegl et al., Nano Lett. 2025, 25, 13996.
[3] Hofmann et al., Angew. Chem. Int. Ed. 2023, 62, e202213982.
[4] Constantinou et al., Nat. Commun. 2024, 15, 694.
[5] Constantinou et al., Adv. Sci. 2023, 10, 2302101.