AFM Scan Results

2D Materials AFM Scan Results

Our Nano-Observer AFM series is a cutting-edge solution for the analysis of 2D materials like graphene, hBN, and transition metal dichalcogenides. It offers unparalleled precision in characterizing surface morphology, mechanical properties, and electrical behavior at the nanoscale. With advanced modes such as HD-KFM III and ResiScope, it enables detailed investigations of these materials' unique properties, supporting both fundamental research and industrial development in nanotechnology and advanced material applications.

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AFM for 2D materials

Which AFM for graphene, hBN and MoS₂?

Topography alone says little about a 2D material: one extra atomic layer changes the work function and the conductivity, and moiré superlattices can be invisible in height images. What matters is electrical contrast at nanometre resolution. The Nano-Observer II AFM from CSInstruments combines the modes that give it on the same sample:

  • Layer counting and work function — HD-KFM™, single-pass Kelvin probe force microscopy (KPFM), distinguishes graphene from one to four monolayers.
  • Moiré domains — in folded hBN, HD-KFM™ resolves triangular domains of about 100 nm at a 1 µm scan, while the topography is atomically flat; PFM shows the same pattern.
  • Conductivity — ResiScope™ maps resistance over 10 decades; on few-layer MoS₂ it is recorded on the same area as the work function.
  • Flakes on a substrate — resonant-mode phase separates graphene flakes from the SiO₂ underneath.

2D materials application noteHD-KFM™ III

Images

Graphene Sample on Si (HD-KFM · 20x20 µm)
Graphene Sample on SiHD-KFM · 20×20 µmHD-KFM Mode · Surface Potential Measurement · Scan size: 20×20 microns
Hexagonal boron nitride (hBN)
Hexagonal boron nitride (hBN)HD-KFM III10 microns size HD-KFM III and PFM measurement of a folded hBN device. Topography shows that surface is atomically flat, while surface potential shows regions with characteristic moiré patterns. This patterns indicate the presence of domains with parallel alignment of the polarization vector. The visible contrast in the SP domains is compatible with AB and BA atomic arrangement (see inset). Alternatively PFM measurement also shows similar characteristic Moiré pattern.
Hexagonal boron nitride (hBN)
Hexagonal boron nitride (hBN)HD-KFM · 25×25 µmHD-KFM scans of hexagonal boron nitride (hBN) were performed, starting with a 25×25 µm area, followed by a 10×10 µm region, and finally zooming into a 4×4 µm spot. The last scan clearly shows Moiré pattern with triangular domains of ~100nm.
Hexagonal Graphene Flakes
Hexagonal Graphene FlakesphaseResonante Mode image (3 micron size- phase channel) of a SiO2 substrate (red area) with hexagonal graphene flakes. (green domains) on some of the flakes a second hexagonal monolayer is measured (blue areas)

Videos

Graphene

Application Notes – 2D Materials

FAQ

Frequently Asked Questions

What is the best AFM technique for graphene and other 2D materials?

Electrical AFM modes, because the layer number and stacking of 2D materials show up in the work function and the conductivity more than in the topography. Single-pass KPFM (HD-KFM) maps the work function, ResiScope maps resistance and PFM maps polarization domains; the Nano-Observer II combines them on the same sample.

Can AFM count the number of graphene layers?

Yes. HD-KFM surface potential distinguishes graphene regions from one to four monolayers by their work function, with sharp interfaces between layers.

Can AFM image moiré patterns in hBN?

Yes, in the surface-potential channel. HD-KFM resolves triangular moiré domains of about 100 nm in folded hBN at a 1 µm scan, while the topography is atomically flat. PFM shows the same moiré pattern.