High Responsivity of Suspended MoS₂ Photodetector via van der Waals Contact

High-performance photodetectors require a reduction of the Schottky barrier at the metal-semiconductor interface. Here, we fabricate a suspended multilayer molybdenum disulfide (MoS2) flakes photodetector divided into symmetric and asymmetric (with different contact lengths between MoS2 and the metal electrodes) devices that can balance responsivity and response time. Due to the van der Waals contact, the symmetric suspended MoS2 photodetector shows high responsivity (upto 307.66 A
$\cdot $
W-1) in the visible range, short response time (
$\tau _{\text {rise}}$
/
$\tau _{\text {decay}} =0.25$
/0.24 s), high specific detectivity
${D} ^{\ast }$
(upto
$4.55\times 10^{{11}}$
Jones), and high external quantum efficiency (EQE) (upto 60000%). The design of the suspended MoS2 photodetector can be extended to other monolayer or multilayer 2-D materials, providing ideas for a list of high-performance optoelectronic devices.