Research On The Photoresponse Of Gold Nanofilms And Carbon Nanotubes

Photoresponse is a physical process of using the interaction between light and matter to convert optical information into electrical signals.At present,there are a series of photodetectors of various types working in the?-ray,X-ray,ultraviolet light,visible light,infrared light and terahertz band.The development of society and the progress of science and technology put forward new requirements for the performance of photodetectors,such as high sensitivity,fast response,low power consumption and wide spectrum.In order to meet these requirements,researchers need to continuously discover new photoresponse mechanism,find new photoelectric response materials,construct new device structure and develop new technology.This paper focuses on the broadband photoresponse based on the synergistic effect of surface ions and plasmon polaritons in the composite structure of gold nanofilm and superionic conductor,and systematically studies the ultra-broadband photoresponse based on the suspended carbon nanotube films and the high-performance terahertz photodetector based on the suspended carbon nanotube fibers.First,we used the composite structure of gold nanofilm and superionic conductor Rb Ag₄I₅ to realize the broadband photoresponse from ultraviolet to near-infrared,and the response performance was much better than that of the pure gold nanofilm.The photocatalytic solid-state electrochemical reaction between Rb Ag₄I₅ and gold nanofilm was experimentally confirmed,and the diffusion processes of Au⁺in the photoresponse was analyzed using an ionic diffusion model.Then the photoresponse mechanisms under different wavelengths of light were analyzed by combining the effects from the surface plasmon polaritons.Finally,we experimentally confirmed that Au⁺could be transported in Rb Ag₄I₅ and the surface morphology of gold nanofilms was modified by the photocatalytic solid-state electrochemical reaction between gold and Rb Ag₄I₅ to regulate.Secondly,ultra-broadband photoresponse from ultraviolet to terahertz band was realized by using carbon nanotube films with wide diameter distribution.In addition,from the perspective of bolometer,the different response performances of devices with different sizes under illumination of light with different wavelengths were calculated and analyzed theoretically.Finally,we investigated the reasons for the differences in the photoresponse properties of different carbon nanotube films according to the Raman spectroscopy,and preliminarily optimized the device performance.Finally,the high-performance terahertz photoresponse at ambient condition was achieved by suspended carbon nanotube fibers.The theoretical model suitable for carbon nanotube fibers was verified experimentally,and the different performances of devices with different channel lengths were compared,which laid a foundation for further optimization in the future.Finally,we also demonstrated the potential application of suspended carbon nanotube fibers as ultra-broadband photoresponse devices.This paper paves new ways for the study of photodetectors based on gold nanofilm and carbon nanotubes,deepens the understanding of photoresponse performance of these two materials theoretically and experimentally,and the sensitivity,spectral of photoresponse and response speed of the photodetectors based on such materials are expected to be constantly improved through a reasonable design of the structure and a parameter optimization.