| Since Carbon nanotubes(CNTs) were discovered in 1991,CNTs properties have been attracted many scientists' attention.CNTs can be used in many fields due to its excellent properties of mechanics,electricity.CNTs have a high aspect ratio,low work function,good electrical conductivity and nanometer tip,which can emit electrons at low voltage.So CNTs are considered as a good field emission cathode.It is believed that CNTs will have a widely application in field emission display.The thesis starts with the history of the development of the cold cathode with emission field emission display.In the next place,we describe particular of Carbon nanotubes,it introduces Carbon nanotubes structure,its growth principle,the traditional technology of producing,applications of Carbon nanotubes,characteristics of Carbon nanotubes and investigating Carbon nanotubes.Carbon nanotubes deposited on metal substrate by chemical vapor deposition(CVD) and Carbon nanotubes have a simple purification method.Thereafter,The CNTs cathodes are also fabricated by screen-printing method.The purification of CNTs,the preparation of CNTs paste,the technique of screen-printing method and the sinter of the sample are studied.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured using diode structure in a vacuum chamber.Finally,the several treatments are produced to improve he field emission characteristic of screen-printed CNT cathodes.The change of surface morphology for CNT cathodes and CNTs characteristic are examined by SEM,TEM and Raman spectrum.The ways to fabricate satisfying CNT field emission cathodes by screen-printing are found.The major results are listed as follows.1.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured.Results showed that the prepared CNTs film have better field emission properties,with turn-on field of 2.4V/μm, current density of 117.7μA(at 3.1V/μm).2.The CNTs cathodes are fabricated by screen-printing method and the field emision properties of CNTs cathodes are measured.A post-treatment method by hard hairbrush was presented to solve the problem of poor field emission characteristics of printed CNT films.The results showed that the field emission properties of CNTs film are a very significant improvement.Compared to those of untreated film,the turn-on electric field of the treated film decreased from 2.4 to 1.4 V/μm,and the total emission current of the treated film that has the same printing area as the untreated one increased from 105.1 to 1379.4μA(at 3.0 V/μm),and more uniform emission and more stability emission have also been observed.3.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured.A post-treatment method by electrical treatment was presented to solve the problem of poor field emission characteristics of printed CNT films.The results showed that the field emission properties of CNTs film are a very significant improvement.Compared to those of untreated film,the turn-on electric field of the treated film decreased from 2.4 to 1.6 V/μm,and the total emission current of the treated film that has the same printing area as the untreated one increased from 94.8 to 896.7μA(at 3.0 V/μm),and more uniform emission and more stability emission have also been observed.4.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured.A post-treatment method, including hard hairbrush and electrical treatment,was presented to solve the problem of poor field emission characteristics of printed CNT films.The results showed that the field emission properties of CNTs film are a very significant improvement. Compared to those of untreated film,the turn-on electric field of the treated film decreased from 2.4 to 1.4 V/μm,and the total emission current of the treated film that has the same printing area as the untreated one increased from 117.7 to 1642.4μA (at 3.1V/μm),and the fluctuation of the total emitting current was decreased from 20%to 5%,and more uniform for field emission have also been observed. 5.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured.A post-treatment method in NaCl electrolyte was presented to solve the problem of poor field emission characteristics of printed CNT films.The results showed that the field emission properties of CNTs film are a very significant improvement.Compared to those of untreated film,the turn-on electric field of the treated film decreased from 2.4 to 1.4 V/μm,and the total emission current of the treated film that has the same printing area as the untreated one increased from 102.6 to 1864.2μA(at 3.0V/μm),and more uniform emission and more stability emission have also been observed.6.The CNTs cathodes are fabricated by screen-printing method and the field emission properties of CNTs cathodes are measured.A post-treatment method by hard hairbrush was presented to solve the problem of poor field emission characteristics of printed CNT films.The results showed that the field emission properties of CNTs film are a very significant improvement.Compared to those of untreated film,the turn-on electric field of the treated film decreased from 2.4 to 1.4 V/μm,and the total emission current of the treated film that has the same printing area as the untreated one increased from 117.7 to 2374.6μA(at 3.0V/μm),and the fluctuation of the total emitting current was decreased from 20%to 4%,and more uniform for field emission have also been observed.
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