Of the two-dimensional materials, "one of the most exposed … is graphene", (Cao and Chen, referring to , "which updates the interest in inorganic materials with its unique electronic and optical applications and high mobility" (Cao and Chen, and references therein). In graphene, "the absence of the bandgap is a limitation for its electronic applications, especially as transistors. In contrast, the transition-metal dichalcogenides (TMDs), quasi-2D materials …, possess non-zero bandgaps that could also be tuned" (Cao and Chen and reference therein).