High-Throughput Photoluminescence Characterization of Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) are two-dimensional layered semiconductors that are exploited in optoelectronic devices such as light-emitting diodes, photodetectors, and photovoltaic cells. Fabricating these devices requires finding high-quality TMD monolayers with favorable optical properties. Flakes are often investigated via photoluminescence (PL) characterization, giving access to information about the optical band gap and the defect density of a crystal. However, such measurements are time-consuming, limiting studies to a small number of flakes. Here, we report a fully automated PL characterization method for TMDs. We present a study of more than 2400 monolayers and bilayers of WSe₂, MoSe₂, and MoS₂. We investigate geometric and PL properties with a previously unattainable number of flakes, revealing significant variations of PL intensity across the monolayers. Additionally, investigated flakes show a strong correlation between PL intensity and the size of the crystal, which is attributed to reduced PL at the edges of monolayer TMDs. We anticipate that our methodology will aid the growth of high-quality TMDs, enhancing their performance for optoelectronic devices.