Regensburg 2019 – wissenschaftliches Programm
HL 27.11: Vortrag
Mittwoch, 3. April 2019, 12:15–12:30, H36
Understanding the formation of interlayer excitons in the case of MoS2 on GaSe. — •Christian Wagner1,2, Mahfujur Rahaman2, Dietrich R.T. Zahn2, and Sibylle Gemming1,2 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Institute of Physics, Technische Universität Chemnitz, Chemnitz, Germany
The fabrication of hybrid van-der-Waals heterostructures of two-dimensional nano materials is an emerging field of study: The (weak) electronic interaction between two layers is often reasonably described by a perturbation of the physical effects of the isolated layers, such as electrostatic doping and screening of intralayer excitons. However, it turns out that this picture of the weak interaction is not exhaustive in terms of optical properties: the formation of bound excitons from electrons of one layer and the holes from another layer yields the formation of interlayer excitons. These states are measured experimentally by photoluminescence and photocurrents, e.g. in the case of MoS2 on GaSe due to type-II band alignment.
This contribution elucidates the conditions for the formation of interlayer excitons from a first-principles point of view. For this, first-principles studies of a minimal test system are conducted. One perspective is then to predict these states as a function of the heterostack in order to specifically taylor efficient solar cells.