Research On The Fabrication And Application Of Au Nanowire Electrode Based On Nanometer Mechanical Scratching

Metal nanowires are widely used in the field of sensors because of their unique optical,electrical and magnetic properties,and have unprecedented application potential.The nano-mechanical scratching method based on atomic force microscopy(AFM)probe is an important method for machining micro-nanostructures.Although the method can control the position of nanowires,the wear of the probe tips is serious during the scratching process,and the size of nanowires cannot be precisely controlled.Due to the small size of the nanowires,subsequent preparation process of the sensor is relatively cumbersome,and the research on the factors affecting the quality and electrical properties of the nanowires is less.Therefore,this paper mainly studies on the method of efficiently fabricating nanowire electrode based on nano-mechanical scratching and lithography technology,and the electrical performance is analyzed.In this thesis,there are mainly three parts of research as follows:Firstly,establish the model scratching on polymethyl methacrylate(PMMA)based on AFM probe.Considering the geometrical shape of the probe tip,the flow stress and viscous frictional force,the thickness of the PMMA film,the pile-up of the material and the influence of the substrate on the film,and according to the force balance condition,the load required for just scratched through the PMMA film with the specific thickness is obtained,then the theoretical model is verified.Secondly,the preparation of nanowire electrode is carried out under the guidance of theoretical model.The preparation process and influencing factors of nanowire electrode are introduced in detail.The nanowires are prepared by AFM probe nanomechanical scratching and lift-off method.The peripheral circuits are prepared by lithography and lift-off.The influence of the distance between the evaporation source and the plating,the electron beam current and the coating time on the quality of the nanowire electrode are studied in the electron beam evaporation coating process.Finally,the electrical properties of the nanowire electrode are measured by the digital source table and the probe table.The resistivity of the external circuits and nanowires of Au and Ti are measured respectively,and compared with the volume resistivity.The effects of length,width and height of nanowires on the electrical properties are mainly studied.The effects of nanostructures on nanowires and surface thiol adsorption on the electrical properties are investigated.At last,a single and arraybased Au nanowire electrodes sensor are fabricated.