Epitaxy of GaSe Coupled to Graphene: From In Situ Band Engineering to Photon Sensing
Journal article, 2024
2D semiconductors can drive advances in quantum science and technologies. However, they should be free of any contamination; also, the crystallographic ordering and coupling of adjacent layers and their electronic properties should be well-controlled, tunable, and scalable. Here, these challenges are addressed by a new approach, which combines molecular beam epitaxy and in situ band engineering in ultra-high vacuum of semiconducting gallium selenide (GaSe) on graphene. In situ studies by electron diffraction, scanning probe microscopy, and angle-resolved photoelectron spectroscopy reveal that atomically-thin layers of GaSe align in the layer plane with the underlying lattice of graphene. The GaSe/graphene heterostructure, referred to as 2semgraphene, features a centrosymmetric (group symmetry D3d) polymorph of GaSe, a charge dipole at the GaSe/graphene interface, and a band structure tunable by the layer thickness. The newly-developed, scalable 2semgraphene is used in optical sensors that exploit the photoactive GaSe layer and the built-in potential at its interface with the graphene channel. This proof of concept has the potential for further advances and device architectures that exploit 2semgraphene as a functional building block.
2D semiconductors
graphene
sensors
gallium selenide
Author
Jonathan Bradford
University of Nottingham
Benjamin T. Dewes
University of Nottingham
Mustaqeem Shiffa
University of Nottingham
Nathan D. Cottam
University of Nottingham
Kazi Rahman
University of Nottingham
Tin S. Cheng
University of Nottingham
Sergei V. Novikov
University of Nottingham
O. Makarovsky
University of Nottingham
James N. O'Shea
University of Nottingham
Peter H. Beton
University of Nottingham
Samuel Lara Avila
National Physical Laboratory (NPL)
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Jordan Harknett
Loughborough University
M. Greenaway
Loughborough University
Amalia Patane
University of Nottingham
Small
1613-6810 (ISSN) 1613-6829 (eISSN)
Vol. 20 40 2404809Subject Categories
Condensed Matter Physics
DOI
10.1002/smll.202404809
PubMed
39169700