Accurate and Fast Thickness Measurement of 2D Materials

Two-dimensional (2D) material flakes have extraordinary quantum qualities not seen in ordinary materials because they have only one to a few layers of atoms. As a result, these materials have enormous potential for advanced research and industrial applications.

In the past, ellipsometry has been a commonly used optical method for noninvasive measurement of thin film thickness. Commercial ellipsometers, on the other hand, have difficulty measuring areas smaller than 50–60 microns, whereas 2D flakes often only have lateral dimensions of a few microns.

Spectroscopic Micro-Ellipsometer (SME), a system and method for an ellipsometer integrated with a microscope, was created and patented by Prof. Ronen Rapaport and Ralfy Kenaz from Hebrew University in responding to this great challenge.

With this sophisticated tool, thin film thickness measurements in very small areas—down to as little as 2 microns wide—can be performed quickly and with atomic-level accuracy. The instrument’s excellent performance has been confirmed in different publications, increasing its legitimacy and dependability.

Researchers from Hebrew University used this state-of-the-art micro-ellipsometer to address current scientific challenges in measuring and mapping the thickness of atomically thin flakes of 2D material in a new study published in the journal. ACS nano.

The results clearly show that the micro-ellipsometer can measure and map the thickness of various flakes of 2D material, allowing estimation of the number of atomic layers.

The results of this study have far-reaching ramifications for various microenterprises and related research domains. They pave the way for highly precise optical microstructural studies, which will lead to technological improvements and new horizons in science.

This research provides a new and invaluable system for researchers and companies by introducing the application of well-established and highly sensitive ellipsometry techniques to microstructures.

There are many possible uses of the Spectroscopic Micro-Ellipsometer in the thin film industry, including wafer quality control, characterizing 2D devices and nanoscale metamaterials, and examining the crystal structure of nanoparticles.

Prof. Laboratory Hadar Steinberg, also from the Racah Institute of Physics at Hebrew University, specializing in the study of 2D materials, collaborated with Prof.’s lab. Ronen Rapaport of the Racah Institute of Physics, known for his expertise in optical investigations.

Journal Reference

Kenaz, R., et al. (2023) Thickness Mapping and Layer Number Identification of Exfoliated Van der Waals Materials with Fourier Imaging Micro-Ellipsometry. ACS nano. doi:10.1021/acsnano.2c12773.

Source: https://id.huji.ac.il/