2 research outputs found
Photo-physics and electronic structure of lateral graphene/MoS2 and metal/MoS2 junctions
Integration of semiconducting transition metal dichalcogenides (TMDs) into
functional optoelectronic circuitries requires an understanding of the charge
transfer across the interface between the TMD and the contacting material.
Here, we use spatially resolved photocurrent microscopy to demonstrate
electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2)
interface. A 10x larger photocurrent is extracted at the EG/MoS2 interface when
compared to metal (Ti/Au) /MoS2 interface. This is supported by semi-local
density-functional theory (DFT), which predicts the Schottky barrier at the
EG/MoS2 interface to be ~2x lower than Ti/MoS2. We provide a direct
visualization of a 2D material Schottky barrier through combination of angle
resolved photoemission spectroscopy with spatial resolution selected to be ~300
nm (nano-ARPES) and DFT calculations. A bending of ~500 meV over a length scale
of ~2-3 micrometer in the valence band maximum of MoS2 is observed via
nano-ARPES. We explicate a correlation between experimental demonstration and
theoretical predictions of barriers at graphene/TMD interfaces. Spatially
resolved photocurrent mapping allows for directly visualizing the uniformity of
built-in electric fields at heterostructure interfaces, providing a guide for
microscopic engineering of charge transport across heterointerfaces. This
simple probe-based technique also speaks directly to the 2D synthesis community
to elucidate electronic uniformity at domain boundaries alongside morphological
uniformity over large areas