Highly Accurate Thickness Determination of 2D Materials

Abstract

Determining the thickness of two‐dimensional (2D) materials accurately and reliably is highly necessary for multiple investigations, but at the same time it can be quite complex. Most studies in this field measure a topographic map at the edge of the 2D material using an atomic force microscope (AFM), and plot a single‐line cross‐section using the software of the AFM. However, this method is highly inaccurate and can result in high relative errors due to surface roughness and line‐to‐line variability. This is even more important in ultrathin (<4 nm) 2D materials grown by chemical vapor deposition, as these exhibit a larger surface roughness (compared to mechanically exfoliated) due to the high density of local defects. Here it is shown that the thickness of ultrathin 2D materials can be determined statistically with high accuracy and reliability in a very easy way by plotting the histogram height plot. Using this method should enhance the reliability of investigations and research papers in the field of 2D materials.