| Owe to the processing technology compatible with traditional complementary metal oxide semiconductor(COMS)electronics,semiconductor films have been widely utilized in the research of photodetectors.However,the defects including grain boundaries in semiconductor films will give rise to scattering of the carriers and thus the decrease of carrier mobility,which leads to the poor photoresponse performance in semiconductor films-based photodetectors.Meanwhile,the critical bending strain of semiconductor films is low,which limits its application in flexible photodetectors.In order to solve the above problems,graphene films with high carrier mobility and excellent mechanical flexibility are combined with semiconductor films to form heterostructures,and the ZnSe single crystal nanowire films are used to replace ZnSe nanocrystalline films as photosensitive material,so as to improve the photoresponse performance and mechanical flexibility of the photodetectors.(1)In order to carry out the comparative experiments,graphene/ZnSe nanocrystalline films heterostructures-based photodetectors were fabricated and the performance test was carried out.The test results show that under the conditions at an applied voltage of1 V and 365 nm UV light illumination with the power of 1 m W/cm2,graphene/ZnSe nanocrystalline films heterostructures-based photodetectors possess the photocurrent of45?A,the response time of 550 ms,the detectivity of 4.2×1012 Jones and the detectable light intensity of 10?W/cm2,and the calculated responsivity value of our fabricated photodetector is up to 1.45×104 A/W.(2)Based on VLS mechanism,ZnSe single crystal nanowire films were grown on graphene films after transfer from Cu foil onto SiO2/Si substrate.Afterward,graphene/ZnSe single crystal nanowire film heterostructures photodetectors were successfully fabricated.The photoresponse results show that under the conditions at an applied voltage of-1 V and 365 nm UV light illumination with the power of 1 m W/cm2,graphene/ZnSe single crystal nanowire film heterostructures photodetectors possess a high photocurrent of 114?A,a fast response time of 50 ms,a high detectivity of6.5×1013 Jones and a low detectable light intensity of 1?W/cm2,and the calculated responsivity value of our fabricated photodetector is up to 2.05×105 A/W.The performance of the as-fabricated photodetectors possesses one order of magnitude enhancement compared with the graphene/ZnSe nanocrystalline films heterostructures-based photodetectors.(3)The flexible photodetectors based on graphene/ZnSe single crystal nanowire films heterostructures were fabricated on 3.5 cm×3.5 cm PET substrate,and the mechanical flexibility was tested.The test results show that the device make a stable performance under the strain of 0.7%and can still work stably under the strain of 0.7%after 10000bending cycles or after 1000 bending hours.Moreover,the flexible photodetectors based on graphene/ZnSe single crystal nanowire films heterostructures meet the requirements of mechanical flexibility and uniformity. |
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