Nanoanalytics

As opto-electronic technology continues to shrink device sizes, precise information on the structure and composition of low-dimensional systems and nanoscale devices becomes essential. The physical properties of the materials are often determined by atomic-scale features, making advanced characterization techniques crucial. This Core Research Area focuses on understanding the fundamental structure-property relation of nanomaterials through high-sensitivity, high-resolution experimental and modeling tools.

This CReA aims to:

Clarify the structure-property relationship in low-dimensional systems.
Provide precise information on the structure, composition, and electronic properties of nanoscale materials.
Develop and apply sophisticated experimental and modeling tools for atomic-scale materials analysis.

Key research areas include:

Epitaxial interfaces and 2D layers: Investigating hetero-interfaces in three dimensions (BALET), interfaces in van der Waals systems and intercalated layers, and extreme heteroepitaxy (PHARAO), exploring the electronic structure of cleaved heterostructures by scanning-probe techniques.
Strain and defect characterization: Understanding strain relaxation mechanisms in anisotropic systems and displacement-induced deformation and (point) defects in 2D materials.
Phase stability and phase transition in epitaxial systems: Studying composition fluctuations, disorder phenomena, and solid-phase epitaxy processes.
Artificial quantum structures: Engineering quantum materials and manipulating atomic structures.

This research leverages PDI’s state-of-the-art signature labs and facilities, including Application Laboratory Electron Tomography (BALET), the PHARAO beamline (BESSYII, Helmholtz-Zentrum Berlin), and Low-Temperature Scanning Tunneling Microscopy (LT-STM), to push the limits of material characterization and manipulation.

CReA Poster 2025

Click the image on the left to view the latest poster from this CReA.

Scientific Highlights

Filmed at the Nano-Scale: How Crystal Defects Rearrange Themselves and Why That Matters for Semiconductor Integration

Threading dislocations are among the most stubborn obstacles to integrating III-V semiconductors on silicon. Filter layers help, but a long-standing puzzle has been why thermal annealing reshapes their internal defect network without actually reducing dislocation density. In this scientific highlight, we present work by researchers at PDI and IES Montpellier who filmed individual dislocations in real time inside an electron microscope and identified the growth conditions under which filtering works best. More…

Reconstruction of 2D metal in the nano-space between graphene and SiC

A new study led by PDI's Van Dong Pham opens new pathways for engineering 2D metals at the nanoscale. The work has been published in Physical Review Materials and selected as an Editors' Suggestion, a distinction awarded to a small fraction of published papers that the editors consider particularly significant and of broad interest to the community. More…

Atomic-Scale Switching of Defects in Two-Dimensional Silver

Scientists at PDI, working within the Core Research Area (CReA) Nanoanalytics, together with colleagues from Penn State University, have demonstrated unprecedented control over atomic-scale defects in a two-dimensional silver layer, opening new possibilities for exploiting defects in two-dimensional metals as functional elements in future nanoelectronic and quantum devices. Read more…

Silver Monolayer Defects, Vacancies and Impurities, Exhibit Dynamic Behavior under Electron Excitation

Featured in Quantum Zeitgeist: Van Dong Pham from the Paul-Drude-Institut für Festkörperelektronik, alongside Arpit Jain and Chengye Dong from Pennsylvania State University, and colleagues, demonstrate unprecedented control over atomic-scale defects within a single layer of silver positioned between graphene and silicon carbide. The work offers exciting possibilities for both fundamental research and technological applications. Read more…

Improving mobility in InAs quantum wells on GaAs substrate

Featured in Semiconductor Today: Researchers in Germany have reported improved mobility in indium arsenide (InAs) quantum wells (QWs) on gallium arsenide (GaAs) substrates, particularly at cryogenic temperatures less than 120K, from a surface smoothing technique used during molecular beam epitaxy (MBE). The team from Humboldt-Universität zu Berlin, Institut Kurz GmbH, and Paul-Drude-Institut für Festkörperelektronik, see their achievements as particularly interesting for quantum information processing.

Third-Party Funded Projects

Artificial quantum states on semiconductor surfaces created and probed by cryogenic scanning tunneling microscopy
New strategies for dislocation density reduction in monolithic III/V epitaxy on Si (DFG-ANR, 2021-2025)

Selected Publications

2026

Strain-induced reconstruction in two-dimensional silver intercalated between graphene and SiC
Authors: V. D. Pham, B. Zheng, A. Jain, C. Dong, L-S. Lu, Z. W. Henshaw, W. H. Blades, J. A. Robinson, V. H. Crespi, A. Trampert, R. Engel-Herbert
Source: Phys. Rev. Materials 10, 034003 – Published 13 March, 2026
DOI: https://doi.org/10.1103/pc8w-hz4t

2025

Strain relief and threading dislocation reduction in GaSb/AlSb/GaSb heterostructures grown on Si(001) substrate
Authors: K. Graser, A. Gilbert, J.-B. Rodriguez, E. Tournié, A. Trampert
Source: J. Appl. Phys., 137, 205302 (2025)
DOI: 10.1063/5.0268051
Vibration-assisted tunneling through single Au adatoms on two-dimensional WSe2
Authors: H. Kumar, Y. C. Lin, J. A. Robinson, S. Fölsch
Source: Phys. Rev. B, 112, 085414 (2025)
DOI: 10.1103/nfd8-xrc4

2024

Scanning tunneling microscopy of ultrathin indium intercalated between graphene and SiC using confinement heteroepitaxy
Authors: V. D. Pham, C. González, Y. J. Dappe, C. Dong, J. A. Robinson, A. Trampert, R. Engel-Herbert
Source: Appl. Phys. Lett., 125, 181602 (2024)
DOI: 10.1063/5.0223972
Three-dimensional reconstruction of interface roughness and alloy disorder in Ge/GeSi asymmetric coupled quantum wells using electron tomography
Authors: E. Paysen, G. Capellini, E. Talamas Simola, L. Di Gaspare, M. De Seta, M. Virgilio, A. Trampert
Source: ACS Appl. Mater. Interfaces, 16, 4189-4198 (2024)
DOI: 10.1021/acsami.3c15546
Detection of Bi_Ga hetero-antisites at Ga(As,Bi)/(Al,Ga)As interfaces
Authors: E. Luna, J. Puustinen, J. Hilska, M. Guina
Source: J. Appl. Phys., 135, 125303 (2024)
DOI: 10.1063/5.0195965
Quantum dots on the InAs(110) cleavage surface created by atom manipulation
Authors: V. D. Pham, Y. Pan, S. C. Erwin, S. Fölsch
Source: Phys. Rev. Research, 6, 013269 (2024)
DOI: 10.1103/PhysRevResearch.6.013269