Hyperspectral imaging microscopy for thickness measurement and surface characterization of layered MoS2

Due to excellent optical performances, two-dimensional materials have emerged as promising materials for applications like optoelectronic devices, photonic devices, and optical sensors. To better study the unique optical performances of 2D materials, spectroscopy techniques such as reflectance and transmittance spectroscopy, and Raman spectroscopy have been utilized for image acquisition and optical property analysis. Hyperspectral imaging (HSI), a combination of spectroscopy and imaging technique, has been used for characterization and property analysis of new materials. A 3D datacube with the wavelength as z-axis, plus spatial axes x and y, can be acquired, and the spectral information can be extracted for characteristic analysis. With the high demand for area imaging of 2D materials, a microscopic HSI setup with a LED light source working in the visible range was proposed for 2D MoS₂ imaging. The HSI imager using a reflection grating works in line-scanning mode in the range of 380-1000 nm. A 3D datacube of 2D layered MoS₂ was built and processed for thickness measurement and optical property analysis, including single-band analysis of the imaging area, spectral analysis of the interesting area, and comparison with the image acquired by a white-light microscope. Finally, general performances of hyperspectral imaging of 2D MoS2 in the visible range was analyzed and discussed for further optical applications