Construction And Lasing Mode Modulation Of ZnO/Graphene Field Effect Transistors-like

ZnO microrods with natural perfect hexagonal cross-section structure are conducive to the formation of Whispering gallery mode(WGM)lasers.It has broad prospects in short wavelength semiconductor lasers.However,most of ZnO semiconductor lasers are fixed wavelength semiconductor lasers,which limit their applications in military,medical and optoelectronic integrated circuits.Although a lot of reports have been reported on the regulation of zinc oxide laser modes,these methods are limited to the static adjustment of the resonator size to achieve the effect of tuning laser modes.Therefore,how to construct tunable ZnO semiconductor lasers with dynamically tunable laser wavelength has become an important and meaningful research topic.In recent years,the electro-optic effect based on the principle that the refractive index of materials will change under the action of electric field has attracted the attention of researchers at home and abroad.As a single crystal material with optical isotropy,ZnO microrods have significant electro-optic nonlinearity.Graphene has been found to have the advantage of light enhancement and light field limitation in graphene/ZnO composite structure.It has been proved that this characteristic can enhance the non-linear optics in ZnO microrods.The field effect transistor based on the principle of parallel capacitor plate is a classical electronic device which can provide small leakage current and stable electric field.Therefore,we have designed and constructed a graphene/ZnO composite field effect transistorlike device,which is based on the unique electro-optic effect and the voltage control of the field effect transistor.In this case,based on the electro-optic effect of ZnO microrods and the optical field limitation of graphene,the dynamic adjustment of laser wavelength of ZnO microrods is realized by changing the refractive index of ZnO microrods due to the electro-optic effect under the stable electric field provided by the field effect transistor.The main research contents of this paper are as follows:(1)ZnO microrods with controllable size were prepared by Chemical Vapor Deposition(CVD)method.The morphology and structure of ZnO microrods and graphene were characterized by SEM and Raman,and the structure characteristics of ZnO and graphene were characterized.(2)Because band gap,surface plasma and electrical properties of graphene are closely related to the applied electric field,the electrical properties of graphene under external electric field are studied by using field effect transistor,and then the graphene surface is modified by oxygen plasma etching technology,and the graphene/ZnO is studied and analyzed from both electrical and Raman spectroscopy aspects.At the same time,graphene/ZnO composite structure field effect transistor-like is constructed,and the role of graphene in the composite was analyzed.(3)Based on the systematic study of graphene/ZnO compound structure field effect transistors,the WGM laser spectra of ZnO under electric field were collected.It is found that the wavelength of ZnO WGM laser shifts with the change of back gate voltage,which is attributed to the electro-optic effect of ZnO.That is to say,under the action of electric field,the refractive index of ZnO changes accordingly,which results in the shift of laser wavelength.This result provides a reference for dynamically tuning the wavelength of ZnO laser.