Facile and Reliable Thickness Identification of Atomically Thin Dichalcogenide Semiconductors Using Hyperspectral Microscopy

Nanomaterials

Yen-Ting Chen¹  Yu-Chung Chang¹  Der-Yuh Lin²  Yu-Kai Wang² 

[1] Department of Electrical Engineering, National Changhua University of Education, Changhua 500, Taiwan;Department of Electronic Engineering, National Changhua University of Education, Changhua 500, Taiwan;

关键词: 2d materials;    transition metal dichalcogenides (tmdcs);    hyperspectral microscopy;    thickness identification;    mos₂;    mose₂;    ws₂;    wse₂;    sns₂;    snse₂;   

DOI  :  10.3390/nano10030526

来源: DOAJ

【 摘 要 】

Although large-scale synthesis of layered two-dimensional (2D) transition metal dichalcogenides (TMDCs) has been made possible, mechanical exfoliation of layered van der Waals crystal is still indispensable as every new material research starts with exfoliated flakes. However, it is often a tedious task to find the flakes with desired thickness and sizes. We propose a method to determine the thickness of few-layer flakes and facilitate the fast searching of flakes with a specific thickness. By using hyperspectral wild field microscopy to acquire differential reflectance and transmittance spectra, we demonstrate unambiguous recognition of typical TMDCs and their thicknesses based on their excitonic resonance features in a single step. Distinct from Raman spectroscopy or atomic force microscopy, our method is non-destructive to the sample. By knowing the contrast between different layers, we developed an algorithm to automatically search for flakes of desired thickness in situ. We extended this method to measure tin dichalcogenides, such as SnS₂ and SnSe₂, which are indirect bandgap semiconductors regardless of the thickness. We observed distinct spectroscopic behaviors as compared with typical TMDCs. Layer-dependent excitonic features were manifested. Our method is ideal for automatic non-destructive optical inspection in mass production in the semiconductor industry.

【 授权许可】

Unknown