Study Of Terahertz Detector Based On Two Dimensional Materials

Terahertz wave has unique advantages such as transient,broadband,penetrability and low energy.Therefore,terahertz technology has broad application prospects in geological exploration,broadband communication,environmental monitoring and national security.Terahertz detector,as one of the key technologies of applicationhas,get developement rapidly.Aiming at the slow response time of traditional vanadium terahertz detector,we intend to improve the situation by using graphene material with high electron mobility.The maill research processes arc summed up as following:(1)Application study of THz holographic imaging instrument was carried out in various fields through the design and preparation of solar batteries,ceramic materials,semiconductor bulk and bulk metal sample.In this process,the stability of the instrument is confirmed which lays a foundation for the test of the terahertz detector.(2)A large area of graphene was obtained after the transfer of graphene from the copper foil to the silicon substrate by the wet transfer technique.The characteristic peaks of graphene were found in the process of Raman characterization.Meanwhile,the defect peak was smaller which indicated the transferred graphene had good quality.(3)Graphene field effect transistor(FET)device was successfully prepared by semiconductor device technology and the device was characterized by photoelectric testing platform.By analyzing the output characteristic curve,it can be found that the contact between the electrode and the graphene material is good and the resistance of the graphene can be calculated by the curve.By analyzing the transfer characteristic curve,it can be concluded that the graphene is P doped which is mainly due to the introduction of water vapor,oxygen and other small molecules in the process of graphene transfer and lithography.(4)The vanadium oxide film was successfully prepared on the graphene device by sputtering and photolithography.Finally,the vanadium oxide-graphene terahertz detector was formed.The vanadium oxide thin film was characterized by X ray diffractometer and the diffraction peak of vanadium oxide was found at 28 position.By exploring the way of combination of vanadium oxide thin films and graphene devices,the vanadium oxide thin film is located above the central area of graphene which avoided the large area damages of graphene in the transfer process.The terahertz holographic imager is used as a terahertz source to test the device.Although the performance of the device needs further improvement,the feasibility of the scheme has been confirmed from the technological perspective.