Atomically thin layers of semiconducting transition metal dichalcogenides (S-TMDs) represent a new class of materials which are of vivid interest, primary in the area of the semiconductor physics and nanoscience as well as opto-electronic applications. The studies of thin films of S-TMDs are greatly inspired by and profit from the research and developments focused on graphene-based systems. Viewed as a part of the “beyond graphene research”, the studies of thin films of S-TMDs are largely at the level of basic research, aiming to enlighten their fundamental properties and potentially new functionalities. The investigations of optical properties represent one of the main directions of research on S-TMD layers.
