2D-InTune · Tuning the electronic structure of two-dimensional semiconductor junctions
Horizon Europe — Marie Skłodowska-Curie Actions
- Duration
- 2023-07-01 → 2025-06-30
- EU contribution
- €173,847
- Participants
- 2
- Scheme
- HORIZON-TMA-MSCA-PF-EF
Lines connect the coordinator with its partners.
Results in brief
Tuning the electronic structure of two-dimensional semiconductor junctions
Modern electronics increasingly relies on atomically thin “two-dimensional” (2D) materials whose properties can be tailored by stacking or joining different layers. A central challenge is to control what happens at the interfaces—where charge enters or leaves a 2D layer and where band bending, screening and strain can dramatically change device performance. Reducing contact resistance, achieving stable junctions and preserving the intrinsic properties of the active layer are all essential for energy-efficient, scalable technologies. This project addresses these needs by combining molecular beam epitaxy (MBE) growth with low-temperature scanning tunnelling microscopy and spectroscopy (STM/STS), low-energy electron diffraction (LEED) and qPlus AFM/KPFM. The overall objective is to establish design rules for 2D junctions at the atomic scale, demonstrated on three model systems: (i) interfacial tuning of MoS2 via controlled self-intercalation at the 2D/metal interface; (ii) MBE-grown lateral MoS2–TaS2 heterojunctions as a route to low-barrier contacts; and (iii) the quasi-freestanding growth of ReS2 on graphene/Ir(111) to access the intrinsic, anisotropic properties of ReS2. Together, these efforts aim to enable reliable, low-power 2D devices and to provide robust, shareable workflows for the wider community.
Data: CORDIS, © European Union
Project objective
Lateral junctions between two-dimensional (2D) semiconductors are conceptually the smallest possible electronic devices. This project investigates the basic physics of these systems as the type of band alignment, the band bending and depletion region, which are decisive parameters for any application. Semiconductor junctions composed of 2D transition metal dichalcogenides (TMDs) will be prepared on hexagonal boron nitride (hBN) or graphene (Gr) on Ir(111). The use of the single-crystalline metal substrate allows the application of surface science methods for preparation and characterization, while the ultrathin buffer layer leaves the intrinsic properties of TMDs undisturbed. Intercalation of guest atoms between the buffer layer and Ir will be used as an elegant and non-invasive method for doping the TMDs. This will also tune intrinsic band bending at the 1D-interface of the TMD junctions, which is yet to be explored for various 2D systems. To separate the effect of inhomogeneous doping and inhomogeneous structure, two types of lateral TMD junctions will be prepared: Homojunctions will be achieved by doping only one part of the TMD island by extending it over the interface of intercalated patches in hBN. Heterojunctions will be composed of two different TMD materials grown on homogeneous vdW substrate, either fully intercalated or pristine. Samples will be prepared by combining two TMDs (ReS2 and WS2) and two dopants (n and p). Scanning tunneling spectroscopy (STS) and Kelvin probe force microscopy (KPFM) will be used for the characterization of the 1D-interfaces and the reconstruction of the band diagrams. Dielectric screening induced by the substrate will be analyzed by comparing values of the band gaps and shifts of critical energy points between different systems. This will deepen the understanding of the origin of band bending in 2D systems. Inelastic electron tunneling spectroscopy (IETS) will be used as a potentially new technique for detecting excitons.
Original text from CORDIS.
Participants
Links
- View on CORDIS
- DOI: 10.3030/101107288
- https://ec.europa.eu/research/participants/documents/downloadPublic?documentIds=080166e51751d668&appId=PPGMS
- https://ec.europa.eu/research/participants/documents/downloadPublic?documentIds=080166e51cf81f60&appId=PPGMS
Data: CORDIS, © European Union