CSInstruments' Nano-Observer II has leveraged several recent developments in atomic force microscopy (AFM) techniques, allowing researchers to capture unprecedented details of two-dimensional materials’ surface and electrical properties.
Its combination of advanced scanning modes enables the comprehensive characterization of hexagonal boron nitride (hBN), graphene, and transition metal dichalcogenides at the nanoscale.
Nano-Observer II – An advanced AFM to analyze 2D Materials. Image Credit: CSInstruments
Advanced Measurement Techniques for 2D Materials
The Nano-Observer II provides the cutting-edge measurement modes to analyze 2D Materials.
1. HD-KFM III - High-Definition Surface Potential Mapping
This mode leverages a multi-frequency approach combined with amplification of the electrical signal through the second eigenmode resonance to enable enhanced sensitivity. It achieves 25 nm edge resolution (even less resolution depending on the sample), operating at 0.1-0.5 nm tip-sample distance.
HD-KFM III can also be combined with other electrical modes like Soft PFM and Soft ResiScope without the need of any change in the setup (one-click operation in the software).
10 microns size combined HD-KFM III and PFM measurement of a folded hBN device. Both modes show characteristic Moiré pattern. 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. Image Credit: CSInstruments
Graphene Layer Potential Measurements
Graphene flakes on SiO2 substrate. HD-KFM shows graphene flakes of different thickness (1 ML, 2ML and 3 ML)
Image Credit: CSInstruments
MoS2 Characterization
HD-KFM III measurement on a MoS2 multi-layer. The graph shows that surface potential decreases with increasing number of layers also the calculated work function increases with the number of layers.
Topography (left) shows different layers, while the potential image(middle) also shows different values for each number of layers. Image Credit: CSInstruments
2. ResiScope III - Advanced Conductive Characterization
ResiScope III is the most advanced conductive AFM mode in the market. It provides real-time adjustment of the amplifiers gain so that both insulating and highly conducting materials can be measured. This implies that the user does not need to apply any change in the setup during the measurement. The ResiScope III offer a resistance range from 10² to 10¹² Ω and a current range from 50 fA to 1 mA, and a real-time protection against high-currents damage.
Image Credit: CSInstruments
ResiScope is capable of preventing high currents effects by adding a protective resistance in real-time. Left image shows an example of measurement of MoS2 flake on gold substrate. The ResiScope high current protection allows to measure the flake without damage due to high current from the gold substrate. On the right side it is shown a typical uncontrolled local oxidation damage when using a standard conductive AFM (C-AFM).
Learn more about ResiScope III
3. Soft Intermittent Contact Mode (3rd AFM Mode)
This mode facilitates the non-destructive analysis of soft samples (polymers, delicate 2D materials, low adhesion nanoparticles etc.). This mode is compatible with both measurement of mechanical & electrical properties like PFM, ResiScope or scanning thermal microscopy (SThM).
Image Credit: CSInstruments
Research Applications
The Nano-Observer II’s advanced measurement capabilities support several pioneering applications areas, including:
- Development of quantum computing components
- Optimization of electronic devices
- Defect analysis
- Doping studies
- Interface engineering
Future Implications
The ability to perform comprehensive, nondestructive characterization of 2D materials at the nanoscale expedites developments across various fields. These measurement techniques offer researchers essential insights into material properties in a range of fundamental research and practical applications.
The Nano-Observer II’s powerful combination of multiple measurement modes in a single instrument enables researchers to efficiently obtain vital correlative data - a key factor in advancing understanding of important materials.
Technical Capabilities
The Nano-Observer II can be used to simultaneously measure a range of key sample properties. Its capabilities include:
- Topography analysis with sub-nanometer resolution
- Surface potential mapping
- Piezoresponse characterization
- Current/resistance measurements
It is possible to perform all measurements with the same tip and setup, meaning that it is only necessary to change software mode to accommodate different analyses.
Acknowledgments
Produced from materials originally authored by CSInstruments.
This information has been sourced, reviewed and adapted from materials provided by CSInstruments.
For more information on this source, please visit CSInstruments.