Preliminary Study On Structural Simulation And Preparation Of Infrared Detectors Based On Graphene Plasma Surface Enhancement

Through photodetectors,humans can convert visible light into more accurate electrical signals,thereby expanding the research field of ultraviolet,infrared,and terahertz wavelengths.The surface plasmon effect can significantly enhance the light absorption of photodetectors and thereby enhance their photoelectric conversion capabilities,which has attracted much attention from researchers at home and abroad in recent years.As a representative of two-dimensional materials,graphene has metal like properties and can also excite plasmons.Compared with other metal materials that can excite plasmons,the surface plasmons of graphene can significantly enhance light absorption and promote its own photoelectric conversion ability.In addition to the ultra-fast carrier transport characteristics of graphene,obtaining graphene photodetectors with high response,high sensitivity,and wide spectrum has become one of the international research hotspots.Currently,optoelectronic devices based on the graphene plasmon effect generally have low light absorption and low responsiveness in the infrared band.Aiming at the difficult issues such as the difficulty in obtaining the photoelectric conversion characteristics of existing devices through calculation and simulation,and the difficulty in preparing graphene patterned micro/nano structures,the thesis uses finite difference time domain（FDTD）,optical and electrical simulation software interaction,and other methods in device structure design,optical and electrical simulation software interaction A systematic simulation study has been carried out on the regulation of electrical characteristics,using artificially constructed micro/nano structures to efficiently excite the graphene plasmon effect.The feasibility of realizing high sensitivity,ultra fast response,and wide spectrum detection in the near and far infrared bands using the graphene plasmon resonance effect based on micro/nano structures has been theoretically explored,and a prototype photoelectric device based on the graphene plasmon effect has been preliminarily realized to be controllable.To solve the problem of low light absorption in the infrared band,a device based on metal periodic micro/nano structures to excite graphene plasmons is designed in the thesis.Calculations using finite difference time domain（FDTD）,optical,and electrical simulation interactions show that the use of gold（Au）periodic cross arrays can effectively stimulate the plasmon effect of graphene at specific chemical potentials.The device has a maximum light absorption of over 60%in the near infrared band（1270-2080 nm）,a response of 911.3 A/W,and a specific detection rate of 1.4×10¹⁰Jones,and the detection band can be adjusted accordingly with changes in structural parameters.Secondly,in view of the difficulty in preparing graphene patterned micro/nanostructures and their vulnerability to mechanical damage,the thesis proposes a method for graphene carrier patterning based on periodic micro/nanostructures to excite graphene plasmons.This method uses the geometric characteristics,size,and polarization field strength of ferroelectric domains to inject a local electric field into graphene to form a micro/nanostructure with gradient potential differences,The damage to the graphene lattice caused by the micro/nano processing process is avoided.The simulation results show that the structure operates in the terahertz band（33.9～62.8μm）The maximum light absorption is 28.1%.The device has a responsiveness of 2273 A/W and a specific detection rate of 1.04×10¹¹Jones.And the device can be adjusted by changing structural parameters and the chemical potential of graphene.The above results indicate that excitation of graphene plasmons in different ways can achieve high response in different infrared wavelengths,which has important research value and development prospects for the future application of graphene in the field of infrared detection.