Interlayer Trions in 2D Transition-Metal Dichalcogenide Heterostructures

A dimensionally confined dielectric constant and reduced dielectric screening lead to two-dimensional transition-metal dichalcogenides (TMDs). The confined dielectric constant triggers a strong Coulomb interaction and high exciton binding energies between TMD heterostructures. Here we show a highly efficient interlayer charged exciton or trion formation and its generation sites are present in materials at room temperature. Two different transition metals (Mo, W) and chalcogenide (S, Se) elements were investigated in two different heterostructure combinations (MoS2—WS2 and MoSe2—WS2). Room temperature photoluminescence measurements demonstrate a highly efficient trion formation between and close to the heterostructure interfaces. This study highlights an effective band alignment, strong photoexciting Coulomb interaction, and formation of interlayer trions with different recombination energies. This investigation suggests the possibility of utilizing interlayer trions in promising optoelectronic devices in the future.