Achievement

Graphene is a single layer of carbon atoms with remarkable optical, electrical, thermal, and mechanical properties. However, graphene has a weakness — a zero bandgap — that gives graphene transistors very poor on/off ratios and graphene photocells poor efficiency. To solve this problem, IGERT Fellow Kathryn McGill and collaborators are developing new single-atom-thick materials, such as MoS2, MoSe2, and MoTe2, which have an intrinsic bandgap. In their bulk form, these materials have a layered structure very similar to that of graphite, enabling adaptation of techniques used to originally develop graphene. McGill and her collaborators began their investigation with molybdenum diselenide (MoSe2), monolayers of which are expected to have a bandgap of ~1.5 eV. After growing pure MoSe2 crystals,they isolated some of the first monolayers of MoSe2 in the field, and they are now fabricating transistors and photocells to study the physics of this new monolayer material.