Study Of The Semiconductor Properties Of Mesoscopic Doping Of Proteins

Semiconductor device is one of the most widely used and most powerful inventions for human being in history.Its appearance has played a decisive role on human science and technology civilization.In this paper,from the perspective of semiconductor functional materials,aiming at the prospective idea of using biological protein mesoscopic doped different semiconductor materials to obtain biological protein-semiconductor composites with unique electrical properties,three kinds of composite materials with different systems are designed respectively.The interaction of the inner structure of the composite and the semiconductor properties of the composite as the active layer of FET are investigated experimentally.Firstly,the use of organic semiconducting polymer poly 3,4-ethylene dioxythiophene:polystyrene sulfonic acid(PEDOT:PSS)doping silk fibroin(SF).The conformational changes of silk fibroin and PEDOT:PSS composite films are analyzed by characterization methods of XRD,UV-vis spectrophotometer,FTIR spectrum and Raman spectrum.The film with a uniform thickness and a smooth surface is prepared as an active layer of the organic field effect transistor,and the performance of this composite material is revealed.The semiconductor characteristics with the switching current ratio of?3,the threshold voltage of 20V,and the carrier mobility of 7.9cm2/(V·s)are obtained.Secondly,through mixing the silk fibroin and graphene oxide(GO),the SF-Graphene(SF-G)composite material is successfully prepared after reduction.The structure of the composite was investigated by FTIR and Raman spectrum.It is found that the doping of graphene oxide gives rise to the transition from the random coil to the ?-sheet conformation of the secondary structure of SF.Finally,through the preparation of the back gate field effect transistor,the semiconductor properties of the SF-G composite film are studied by comparing the transfer and output characteristics of RGO as the active layer.It is found that the SF-G composite film exhibits the characteristics of the p-type semiconductor and has Bi-polar current transmission characteristics.Thirdly,the composite material system of wool keratin(WK)and molybdenum disulfide(MoS2)is studied.The ultrasonic exfoliation of wool keratin-assisted MoS2 in aqueous solution is emphatically introduced.The microscopic process of WK exfoliating MoS2 is systematically demonstrate by the theoretical calculations and experimental characterizations.In addition,AFM and Raman spectrum characterization confirmed that the bulk MoS2 is effectively exfoliated to less than 3 layers,and XPS characterization demonstrate that the use of WK keeps chemical properties of the MoS2 unchanged.The experiment compared the exfoliating effect of BSA,and confirmed that WK has better exfoliating ability because of its more thiol groups,and also confirmed that WK-MoS2 nanosheets have excellent biocompatibility and can be used as the suitable exfoliating agent for TMDs two-dimensional materials.The semiconductor properties of the WK-MoS2 composite film is studied by fabricating a field-effect transistor.And we find that unlike typical n-type semiconductor MoS2,WK-MoS2 exhibits p-type semiconductor characteristics.Due to a large number of defects in the thin films,the current characteristics of the thin films are faint and cannot be used as effective devices.