1 research outputs found
Few-Layer WSe<sub>2</sub> Schottky Junction-Based Photovoltaic Devices through Site-Selective Dual Doping
Ultrathin sheets of two-dimensional
(2D) materials like transition
metal dichalcogenides have attracted strong attention as components
of high-performance light-harvesting devices. Here, we report the
implementation of Schottky junction-based photovoltaic devices through
site-selective surface doping of few-layer WSe<sub>2</sub> in lateral
contact configuration. Specifically, whereas the drain region is covered
by a strong molecular p-type dopant (NDP-9) to achieve an Ohmic contact,
the source region is coated with an Al<sub>2</sub>O<sub>3</sub> layer,
which causes local n-type doping and correspondingly an increase of
the Schottky barrier at the contact. By scanning photocurrent microscopy
using green laser light, it could be confirmed that photocurent generation
is restricted to the region around the source contact. The local photoinduced
charge separation is associated with a photoresponsivity of up to
20 mA W<sup>–1</sup> and an external quantum efficiency of
up to 1.3%. The demonstrated device concept should be easily transferrable
to other van der Waals 2D materials