Two-dimensional (2D) materials have gotten a lot of interest because of their unusual features, which offer a lot of promise for the future of nanoelectronics. Because of their rich electronic energy band structure, these materials could be used in new electrical and optoelectronic devices. The features of 2D-based materials are frequently used in these applications. As a result, accurate measurement of critical parameters such as conductivity, carrier density, mobility, interfacial trap density, and so on is critical for the field's advancement.
Scanning tunneling microscopy and spectroscopy (STM/STS) is commonly used for fundamental studies of 2D materials, providing a broad spectrum of highly entangled topological and localized electronic information at the atomic scale. Alfa Chemistry offers STM/STS testing to characterize 2D materials, which is critical to understanding their properties. Contact us today so we can help you with your 2D material testing!
Why STM/STS
STM is a very valuable technique for quality control at the atomic scale, which can understand the intrinsic and extrinsic disorder associated with atomic defects in 2D materials and heterostructures, enabling additional scientific advancements and development toward technological applications.
STM can be used to study surface topography. However, Alfa Chemistry is more focused on the electronic properties of samples that may be studied via STS. It is possible to gain insight into the local density of states (DOS) at the sample surface location where the tip is located by measuring the IV properties.
Fig 1. (a) STM image showing on the right a bP flake ~25 nm high above the graphene substrate on the left. (b) Atomic resolution image obtained on BP at room temperature. (Kumar A, et al. 2019)
Local doping, bandgap mapping, local disorder, direct characterization of band offsets at heterostructure interfaces, and other fine electrical phenomena can all be studied using STM/STS techniques. For example, we used STM to investigate black phosphorus (BP), which is one of the most promising 2D semiconductors due to its layer-dependent bandgap and high charge carrier mobility. Its pleated crystal structure also produces unusual electrical anisotropy, allowing for new angle-dependent electronic and optoelectronic devices. STM enables the study of inherent flaws in BP at different temperatures, leading to the discovery of periodic electronic superstructures.
Service Detail
| Testing Services | Scanning Tunneling Microscopy (STM) |
| Test Temperature | -20 ~ 150℃ |
| Test Module | constant current mode, constant height mode, I-V curve, I-Z curve, etc |
| Sample Type | Film / Bulk |
| Instrument Model | CSPM5500 Scanning Probe Microscope, MFP-3D Atomic Force Microscope |
| Lead Time | 2~3 Weeks |
Our requirements for samples are as follows:
- For bulk sample: The maximum sample size is 45mm×45mm×30mm. Customers please mark the test surface to ensure that the test surface is smooth and clean.
- For film sample: The maximum sample size is 45mm×45mm×30mm. Please contact us for more information.
Note:
- The sample needs to be conductive, and the scanning surface is very clean, very flat, and free of volatiles.
- Powder samples, organic volatile samples and samples containing unstable substances are not accepted.
- Currently we do not support magnetic field testing.
- All samples are non-refundable, please contact us if you have special requirements.
Reference
- Kumar A, et al. (2019). "STM Study of Exfoliated Few Layer Black Phosphorus Annealed in Ultrahigh Vacuum." 2D Mater. 6: 015005.
Please kindly note that our products are for research use only.
