Environmentally sensitive theory of electronic and optical transitions in atomically thin semiconductors

Due to their small size, atomically thin materials are expected to exhibit electronic properties that are highly sensitive to their environment. However, atomically thin semiconductors on a variety of substrates, as well as in their bulk layered phase, exhibit an absorption onset at roughly the same energy. The authors provide a semianalytic theory of the quasiparticle band gap in atomically thin semiconductors and show that environment-induced changes are almost exactly canceled by changes in the exciton binding energy, leaving the absorption onset nearly constant. The presented theory sets limits on the prospect of environmental engineering in atomically thin materials.