Fabrication And Application Of Polymer Resist Pattern By AFM Lithography

Advance in nanofabrication techniques has been an important driving force for the development of nanoscience and nanotechnology.A variety of functional materials,such as plasmonic material,organic/inorganic semiconductors,two-dimensional graphene and transitionmetal dichalcogenides,have extensive application in nanoelctronics,nanophotonics,organic electronics and biomedical sensors.The successful applications of above various materials strongly depend on the fabrication of nanostructures with unique functions by different nanolithography approaches.Up to now,the surge of progresses in high-performance optoelectric devices require to pattern materials with designed features in nanoscale and thus poses critical challenge to the nanolithography techniques.The limitedd resolution,high-costs and lack of flexibility to novel materials of the conventional lithography techniques hinder their applications and motivate the emergence and development of advanced lithography technique.As an alternative method,Scanning Probe Lithography(SPL)has been an attractive mskless approach to fabricate nanoscale structures due to its integrated advantages of supporting high-resolution,low cost,in situ imaging and flexibility to materials.Here,we focus on the fabrication of uniform polymer resist patterns by AFM lithography and their applications.The main research contents of this thesis are as following:Firstly,AFM mechanical lithography was developed to a feasible and reliable lithography technique for patterning polymer resist structures on different substrate(conductor,insulator and flexible substrate).The critical technical parameters during the AFM mechanical lithography process,such as morphology of tips,applied force,scanning speed,substrate baking and polymer molecule weight,were investigated and optimized.Further more,the well defined PMMA templates show excellent reliability in fabricating nano organic light emitting device.Secondly,we fabricated one dimentional PMMA templates for colloidal particles assembly and explored the interaction between particles and template combing experiment results and theoretical simulation.At the same time,we demonstrated the synergetic modulation from groove spatial potential for one dimentional particles arrangement,by comparing the different assembly results in templates by AFM lithography and e-beam lithography respectively.It offers a novel strategy for precisely controlling the one dimentional assembly of sub-20 nm Au colloidal nanoparticles in the broad groove templates by tuning spatial electrostatic potential which extentively reduces the resolution reqirment for template fabrication technique.At last,we developed an approach to construct multiplex ploasmonic structure by AFM mechanical lithography with assist of PMMA.Different size or shape of metal nanoparticles can be effectively patterned by AFM scratching.With precisely controlling the scratching loading force,multiplexed nanostructures of plasmonic nanoparticles can be fabricated,which demonstrate multiplex plasmonic properties and surface-enhanced Raman scattering(SERS)response.Furthermore,it offers an intuitive way to explore the plasmonic effects on performance of organic light-emitting diodes device integrating with multiplexed plasmonic nanostructures.