Hybrid van der Waals p-n heterojunctions based on p-type oxide and 2D MoS
2
Zhenwei Wang, Xin He, Xi-xiang Zhang and Husam N. Alshareef
Materials Science and Engineering, King Abdullah University of Science and Technology
(KAUST), Thuwal, 23955-6900, Saudi Arabia
Presenter contact details:E-mail:
Address: KAUST P.O. Box 4347, 4700 King Abdullah University of Science & Technology
(KAUST), Thuwal 23955-6900, Saudi Arabia
Two-dimensional (2D) materials including transition metal dichalcogenides (TMDs),
graphene, MXenes, and others have received considerable attention in recent years. This is
because of many exciting properties these materials exhibit as they are scaled from the bulk
to atomic scale. The enhancement of the properties of 2D materials at the atomic scale has
opened up many potential applications. A unique feature for novel heterojunctions that
contain 2D semiconducting materials is the formation of van der Waals (vdWs)
heterojunction at the interface. The signature for such system includes weak bonding between
the stacked layers, atomically abrupt change in lattice structure, and excellent inherited
properties from the corresponding 2D semiconductors (
e.g.
TMDs). The weak bonding
between layers allows one to completely get rid of the lattice-epitaxy constraint and thus
substantially increase the potential candidate materials for building vdWs heterojunctions.
The atomically sharp change in lattice structure could bring more fascinating phenomena that
cannot be directly demonstrated by traditional materials fabrication processes, for instance
applications based on the tunneling effect. The merits inherited from TMDs make vdWs
heterojunction an exciting device to study.
Here, for the first time, we demonstrate p-type oxide/n-type 2D hybrid vdWs
heterojunctions based on SnO and MoS
2
, with good diode operating performance, including
ideality factor ~2 and stable rectification ratio up to ~10
4
. MoS
2
with layer numbers of 1, 3 to
7 are used for building junctions, and the device performance shows dependence on the layer
numbers. The reported hybrid vdWs heterojunctions are gate-tunable and exhibit typical anti-
ambipolar transfer characteristics when tested using three-terminal configuration. Surface
potential mapping of the junctions was performed as a function of number of MoS
2
layers,
geometry dependent current flow model through the 2D MoS
2
layers and the hybrid vdWs
heterojunction is proposed. Our work demonstrates p-SnO/n-MoS
2
vdWs heterojunction can
be a robust block in future electronic applications.
PS1 22
-178-
