Abstract
We report the generation of long-lived and highly mobile photocarriers in hybrid van der Waals heterostructures that are formed by monolayer graphene, few-layer transition metal dichalcogenides, and the organic semiconductor F
ZnPc. Samples are fabricated by dry transfer of mechanically exfoliated MoS
or WS
few-layer flakes on a graphene film, followed by deposition of F
ZnPc. Transient absorption microscopy measurements are performed to study the photocarrier dynamics. In heterostructures of F
ZnPc/few-layer-MoS
/graphene, electrons excited in F
ZnPc can transfer to graphene and thus be separated from the holes that reside in F
ZnPc. By increasing the thickness of MoS
, these electrons acquire long recombination lifetimes of over 100 ps and a high mobility of 2800 cm
V
s
. Graphene doping with mobile holes is also demonstrated with WS
as the middle layers. These artificial heterostructures can improve the performance of graphene-based optoelectronic devices.