Light-matter interactions in van der Waals photodiodes from first-principles

Strong light-matter interactions in van der Waals heterostructures (vdWHs) made of twodimensional (2-D) transition metal dichalcogenides (TMDs) provide a fertile ground for optoelectronic applications. Of particular interest are photo-excited inter-layer electron-hole pairs, where electrons and holes are localized in different monolayers. Here, we present an ab initio quantum transport framework relying on maximally localized Wannier Functions and the Non-equilibrium Green’s Functions to explore light-matter interactions and charge transport in 2-D vdWHs from first-principles. Electron-photon scattering is accurately taken into account through dedicated self-energies. As testbed, the behavior of a MoSe2-WSe2 PIN photodiode is investigated under the influence of a monochromatic electromagnetic signal. Inter-layer electron-hole pair generations are observed even in the absence of phonon-assisted processes. The origin of this phenomenon is identified as the delocalization of one valence band state over both monolayers composing the vdWH.
Physical Review B, 106
ISSN:1098-0121
ISSN:0163-1829
ISSN:1550-235X
ISSN:0556-2805
ISSN:2469-9969
ISSN:1095-3795
ISSN:2469-9950