Research On Broadband Photodetector Based On Carbon-based Composite Fil

The development of society and the progress of science and technology are constantly putting forward new requirements for the performance of photodetectors,such as high sensitivity,fast photoresponse,low power consumption and broad spectrum.In order to meet these requirements,researchers need to continuously discover new photodetective materials,construct new device structures and develop new process technologies.Carbon-based films include CNT films and r GO films,both of which are theoretically capable of broad-spectrum photodetection.In this work,two types of thin-film photodetectors,"suspended CNT films modified with Cs_xWO₃ nanoclusters"and"metal/suspended r GO films/metal",were prepared and studied.（i）Proposed the use of CNT films modified with Cs_xWO₃ nanosheets,which have strong infrared absorption,high photothermal conversion efficiency and dynamic characteristics of transient photothermal conversion,to fabricate a Cs_xWO₃-CNT photodetector.The performance shows a significant enhancement of the broad-spectrum photoresponse from the VIS（405 nm）to the SWIR（1550 nm）compared to pure CNT films photodetector.The responsivity was up to 99.65 m A/W,an average improvement of 400%;the specific detectivity was up to 1.69×10⁷ Jones,an average improvement of 549%;and the photoresponse was 28 ms,an improvement of 30%.The results showed that the modification of Cs_xWO₃nanomaterials to CNT films can significantly improve the performance of photodetectors.（ii）A"metal/suspended r GO films/metal"photodetector was fabricated and the effect of channel width and metal type on the performance of the photodetector was studied.Firstly,the photodetectors with channel widths of 100μm and 500μm were fabricated and analysed under different wavelengths of light.The results show that both devices can achieve broad-spectrum photodetect from the UV（375 nm）to SWIR（1550 nm）,and that the short channel can further improve the performance of photodetectors.Then,the self-powered"Pd-suspended r GO films-Ti"photodetector was successfully fabricated by changing the metal type of the detector electrode and selecting metals with different functionalities in contact with the r GO films,achieving a broad spectrum of photodetect from the UV（375 nm）to SWIR（1550 nm）.This paper provides new ideas for the development of photodetector based on carbon-based films.It has deepened the understanding of the performance of carbon-based materials combined with semiconductor materials.And it is expected to further improve the sensitivity,spectral range,photoresponse and other aspects of the device performance by optimizing the device structure and parameters,laying the foundation for the subsequent practicalization.