Synthesis Of Large Area Monolayer Mo S2 And The Modification Of Transistors' Responsivity By Ag Nanoparticles

With Moore's law coming to an end,scientists are now focusing on 1D or 2D materials,which exhibit excellent performance at nanometer scale.With high on/off ratio,considerable mobility and bendable body,MoS₂ has been intensively studied as a representative of 2D semiconductors.The properties of direct bandgap and high surface to volume ratio enable MoS₂ to be an ideal material for photodetection.However,it is now still difficult to prepare large area and high quality MoS₂ crystals,and the responsivity of MoS₂ photodetectors is still relatively low.In order to break these bottlenecks,this paper mainly studies the controllable synthesis of monolayer MoS₂ and the modification of MoS₂ transistors with Ag nanoparticles.The results are as follows:1.The core factor in the growth process of MoS₂ is the vaper pressure of S and MoO₃,and large monolayer MoS₂ crystals could only be synthesized in a specific window.The triangular MoS₂ single crystals we prepared is monolayer,and its side width is as large as178?m.We have confirmed that these crystals are of high quality by characterization using TEM?Raman&PL spectrum and XPS.2.Taking advantage of LSPR effect induced by Ag NPs,we have realized the enhancement of photoresponsivity for MoS₂ transistors.The responsivity shows an evolution with the increase of Ag particle size,and it peaks at the particle size of 25 nm with an enhancement of 470%.The enhanced responsivity is as high as 2.97×10⁴ A W^-1.This work is believed to be of instructive in the synthesis of MoS₂ and the modification of photodetectors.