A Facile Method for Precise Layer Number Identification of Two-Dimensional Materials through Optical Images

TL;DR

This paper introduces an image reconstruction technique that standardizes optical images of 2D materials taken under different conditions, enabling precise layer number identification through color comparison.

Contribution

It presents a novel method to convert raw optical images into standardized images, improving the accuracy of layer number identification of 2D materials using optical microscopy.

Findings

Effective reconstruction of optical images under arbitrary conditions.

Accurate layer number identification for MoS2, WS2, and WSe2.

Enhanced precision of optical microscopy for 2D materials.

Abstract

Optical microscopy is believed to be an efficient method for identifying layer number of two-dimensional 2D materials. However, since illuminants, cameras and their parameters are different from lab to lab, it is impossible to identify layer numbers just by comparing a given optical image with standard or calculated images under standard conditions. Here we reported an image reconstruction method, converting raw optical images acquired by arbitrary illuminants and cameras into reconstructed images at specified illuminant and specified camera. After image reconstruction, the color differences of each layer number roughly equaled those calculated under specified condition. By comparing the color differences in reconstructed image with those calculated under specified condition, the layer numbers of 2D materials in our lab and published papers, including MoS2, WS2 and WSe2, were ambiguously identified. This study makes optical microscopy a precise method for identifying layer numbers of 2D materials on known substrate.