Laser-Assisted Patterning Of Thin-Film Materials

Thin-film materials have been widely used in micro-nano optical devices,metamaterial surface,solar cell,touch panel,micro-electromechanical system(MEMS)and microfluidics chip.Up to now,template-based lithography and nanoimprint are the most common ways to fabricate film materials with micro-nano structure.Hereinto,lithography is the most widely used for the thin film.Processes including photo/electron beam lithography,ultraviolet lithography,and X-ray lithography have been successfully applied in fabricating large-scale and high-revolution micro-nano structure of thin-film materials.However,high-cost of the complicated procedure using templates limits the arbitrary design or customization.Recently,printing and laser direct writing methods without templates have been developed to fabricate micro-nano structure.They have great advantages for designing and customization.For example,they have already found their application in fabricating micro-nano structure of metal,resin,and ceramics.In this thesis,we have developed laser-assisted method to fabricate the diversity of micro-nano structure for graphene film and oxide semiconductor film.Firstly,IR laser is utilized to fabricate micro-nano structure of graphene film to increase the transparence of multilayer graphene film for transparent conductive electrodes.In this work,IR laser is used to selectively ablate regular areas of 300 nm-thick multilayer graphene film to tailor micro-grid structure.By adjusting ablation ration and grid feature,the transparence of graphene film is increased nearly 200 times from 0.38%to 75%while the sheet resistance is only increased 5 times from 70 Q/sq to 340 ?/sq.The corresponding figure of merit(FoM)is increased from 0.1 to 3.6.Moreover,we have successfully applied the obtained graphene grid for electrical-thermal defogger.It is proved the defogger based on graphene grid has a high efficiency of electricity-heat transformation,whose temperature could be increased from room temperature to 60? within two minutes.The thermal field of graphene thin films can be adjusted by patterning grid of laser tailoring.The laser-tailoring strategy provides an efficient route to fabricate micro-nano structure of multilayer graphene film as transparent conductive electrodes.Secondly,laser direct writing is developed to print the diversity of patterning oxide semiconductors.Herein,the crosslink of sugar and metal-coordinated polymer happens for the micro-nano structure of patterned precursor film under the heat of IR laser.Bottom-up growth of patterning metal oxides is carried out during being annealed in air atmosphere.Finally,ZnO,SnO2,NiO,etc.have been successfully patterned as the desirable structures.The study is explored that printing metal oxide semiconductors film have micro-nano structure,high crystallinity,and good electrical performance.All in all,this strategy provides an efficient route to print micro-nano desirable structure of metal oxide semiconductors.