Study Of Molybdenum Disulfide ?MoS₂? Detectors Based On Optical Micro-Structures

As a new generation of semiconductor materials,molybdenum disulfide?MoS₂?brings new opportunities to the development of micro-nano structure detectors.However,in the visible range,the absorption of light is usually less than 10%,which is caused by its ultra-thin atomic layer.Therefore,improving the light absorption ability is also an important problem faced by MoS₂-based detector.Focusing on the topic of the enhancement of detector,this dissertation introduces the photoelectric detector based on MoS₂,including its research progress and some challenges.At the same time,the concept and principle of optical microstructure and the Finite-Element-Method?FEM?are also briefly introduced.Based on the near-field enhancement and surface localization of Surface plasmons Polaritons?Spp?,this dissertation expects to use optical microstructures to enhance the photoresponse of MoS₂-based photodetectors.The specific work and conclusions are as follows:1.The planar microcavity structure was integrated with monolayer MoS₂ to enhance the optical response of the MoS₂-based photodetector.Theoretical simulations show that the optical absorption at the working wavelength can be significantly enhanced,the problem of low absorption of materials can be improved,and the enhancement mechanism is studied through the electric field distribution.At the same time,the photoreaction of the monolayer MoS₂ photodetector based on this microcavity structure is also greatly enhanced,and the device can obtain enhanced photocurrent response at the operating wavelength,making them not only expected to be used for photodetectors,but also for wave division,Electrical absorption modulator and variable optical attenuators.2.Based on the theory of magnetic polarization,this study proposes an irregular metal grating to enhance the broadband absorption of monolayer MoS₂.And the structural model of the optical response of MoS₂ photodetectors based on irregular gratings is also studied.The theoretical model of the magnetic field distribution and the inductance-capacitance?LC?equivalent circuit of the MoS₂ detector structure containing silver?Ag?grating is studied to understand its physical mechanism.The results show that different orders of MPs can form different absorption peaks,achieving wide frequency absorption and adjustable absorption.At the same time,with the help of grating size effect,the absorption and optical response enhancement of MoS₂ photodetectors based on irregular metal gratings are discussed.It is proved that the irregular metal gratings achieve broadband absorption of monolayer MoS₂compared with ordinary metal gratings.And the optical response enhancement of the irregular metal gratings is more effective than the ordinary metal gratings.3.The Surface Plasmon Polaritons?Spp?grating coupling is used to break the conventional mirror-symmetric contact surface structure of metal-semiconductor-metal?MGM?detectors.By using different contact surface structures of the same material,the problem of large dark current caused by traditional MGM detector was improved.The enhancement of the net response is achieved by the interference between the Spp wave and the incident wave with the asymmetric contact surface structure.