10.1021/acsami.8b20321.s001
Tongxin Chen
Tongxin
Chen
Yuewen Sheng
Yuewen
Sheng
Yingqiu Zhou
Yingqiu
Zhou
Ren-jie Chang
Ren-jie
Chang
Xiaochen Wang
Xiaochen
Wang
Hefu Huang
Hefu
Huang
Qianyang Zhang
Qianyang
Zhang
Linlin Hou
Linlin
Hou
Jamie H. Warner
Jamie H.
Warner
High
Photoresponsivity in Ultrathin 2D Lateral Graphene:WS<sub>2</sub>:Graphene
Photodetectors Using Direct CVD Growth
American Chemical Society
2019
photodetecting transistors exhibit
WS 2
Schottky barrier height
2 D ultrathin
van der Waals
prepatterned graphene gaps
Direct CVD Growth
layer-by-layer transfer method
chemical vapor deposition
device
2019-01-31 17:49:20
Journal contribution
https://acs.figshare.com/articles/journal_contribution/High_Photoresponsivity_in_Ultrathin_2D_Lateral_Graphene_WS_sub_2_sub_Graphene_Photodetectors_Using_Direct_CVD_Growth/7655912
We show that reducing the degree
of van der Waals overlapping in
all 2D ultrathin lateral devices composed of graphene:WS<sub>2</sub>:graphene leads to significant increase in photodetector responsivity.
This is achieved by directly growing WS<sub>2</sub> using chemical
vapor deposition (CVD) in prepatterned graphene gaps to create epitaxial
interfaces. Direct-CVD-grown graphene:WS<sub>2</sub>:graphene lateral
photodetecting transistors exhibit high photoresponsivities reaching
121 A/W under 2.7 × 10<sup>5</sup> mW/cm<sup>2</sup> 532 nm illumination,
which is around 2 orders of magnitude higher than similar devices
made by the layer-by-layer transfer method. The photoresponsivity
of our direct-CVD-grown device shows negative correlation with illumination
power under different gate voltages, which is different from similar
devices made by the transfer method. We show that the high photoresponsivity
is due to the lowering of effective Schottky barrier height by improving
the contact between graphene and WS<sub>2</sub>. Furthermore, the
direct CVD growth reduces overlapping sections of WS<sub>2</sub>:Gr
and leads to more uniform lateral systems. This approach provides
insights into scalable manufacturing of high-quality 2D lateral electronic
and optoelectronic devices.