Related Experiment Video
Updated: Jul 23, 2025
11:10
Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model
Published on: May 23, 2018
12.0K
Correlating Optical Microspectroscopy with 4×4 Transfer Matrix Modeling for Characterizing Birefringent Van der Waals
Julian Schwarz1, Michael Niebauer1, Maria Koleśnik-Gray2
1Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Electron Devices, Cauerstraße 6, 91058, Erlangen, Germany.
Small Methods
|July 18, 2023
Summary
Accurately measuring the thickness of Van der Waals materials is crucial for their electronic applications. This study introduces a new optical reflectance method for precise, nondestructive thickness determination, even for encapsulated layers.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Van der Waals materials possess unique electronic and optoelectronic properties.
- Precise thickness control is essential for optimizing device performance.
- Existing thickness measurement techniques have limitations.
Purpose of the Study:
- To develop a nondestructive and easily implementable method for accurate thickness determination of birefringent layered materials.
- To provide a reliable technique for tailoring Van der Waals material properties for device applications.
Main Methods:
- Combining optical reflectance measurements with a modular model.
- Utilizing a 4x4 transfer matrix method and light microspectroscopy.
- Demonstrating the approach on anisotropic materials like graphite and black phosphorus.
Main Results:
- Achieved reliable and precise thickness determination from atomic layers up to >100 nm.
- The method is effective even for encapsulated layers.
- Outperformed state-of-the-art techniques like atomic force microscopy.
Conclusions:
- The developed optical reflectance method offers a robust solution for thickness characterization of Van der Waals materials.
- This technique facilitates the precise engineering of materials for advanced electronic and optoelectronic devices.
Related Concept Videos
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
24.7K
UV–Visible absorption spectra of conjugated dienes arise from the lowest energy π → π* transitions. The light-absorbing part of the molecule is called the chromophore, and the substituents directly attached to the chromophore are called auxochromes. A strong correlation exists between the absorption maxima, λmax, and the structure of a conjugated π system. The Woodward–Fieser rules predict the value of λmax for a given...
24.7K
01:32UV–Vis Spectroscopy of Conjugated Systems
7.1K
Organic compounds with conjugated double bonds show strong absorption features in the UV–visible region of the electromagnetic spectrum attributed to π → π* electronic excitations. Generally, a UV–vis absorption spectrum is recorded as a plot of absorbance vs wavelength. The wavelength of maximum absorbance, which manifests as a peak in the absorption spectrum, is denoted as λmax.
One of the factors influencing λmax is the extent...
One of the factors influencing λmax is the extent...
7.1K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
1.6K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.6K
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.4K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.4K
01:09UV–Vis Spectroscopy: Beer–Lambert Law
3.1K
The Beer-Lambert law describes the relationship between absorbance and concentration, which combines the principles established by scientists Johann Heinrich Lambert and August Beer. Lambert's law states that when light passes through a medium, the loss in intensity is directly proportional to the original intensity and the path length of the light. Beer's law proposed that the transmittance of a solution remains constant if the product of concentration and path length is constant. The...
3.1K
01:14UV–Vis Spectrometers
1.4K
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell.
1.4K