SiC纳米阵列结构调控及其场发射特性研究
发布时间：2018-11-21 16:08
【摘要】：场发射是低维纳米材料的固有特性之一,在显示和真空电子等领域具有广泛的应用前景,是当前国际研究的前沿和热点之一。碳化硅(SiC)是第三代宽带隙半导体,具有优异的力学性能、良好的化学稳定性、低热膨胀系数、高热导率和低电子亲和势,是场发射阴极的优异候选材料之一本论文工作以具有优异电子发射特性的场发射阴极材料研发为目标,通过工艺的探索和优化,实现高定向SiC微尖纳米阵列的生长及其结构调控,以期集局域场增强效应、增加电子发射点和掺杂调控三种方法于一体,实现SiC纳米结构的电子发射能力的协同强化。采用催化剂辅助有机前驱体热解工艺,以聚硅氮烷(PSN)为前驱体提供生长SiC所需的Si源和C源、高纯Ar为保护气氛、碳纸为生长衬底,实现单晶SiC纳米线的制备；在热解过程中引入掺杂剂N和B分别实现n型和p型SiC纳米线的制备；并对关键热解工艺参数如衬底种类、催化剂种类和降温速率进行探索和优化,在6H-SiC(0001)衬底上实现了高定向SiC微尖纳米阵列结构的生长及其结构调控。实现高定向n型和p型SiC微尖纳米阵列场发射阴极的制备,场发射研究结果表明,n型SiC微尖纳米阵列室温下的开启电场为1.50 V/μm,当温度升至500℃时,其开启电场降至0.94 V/0μm,表明实验制备的SiC场发射阴极材料具有优异的场致电子发射能力；调控SiC纳米阵列的密度并研究阵列密度对其场发射性能的影响,采用不同厚度的催化剂Au膜50、70和90 nm,获得密度分别为～2.9×107、-4.0×107和～5.7× 107根/cm2的SiC纳米阵列,其开启电场分别为～1.79、-1.57和～1.95 V/μm,说明合理密度的纳米阵列可增加场发射点的数量和限制场屏蔽效应有利于提高其场发射性能;p型SiC微尖纳米阵列室温下的开启电场为1.92 V/gm,当温度升至500℃时,其开启电场降至0.98 V/μm.在室温和200℃下,p型SiC微尖纳米阵列发射电流密度波动分别为6.5%和7.8%,表明B掺杂的SiC微尖纳米阵列结构具有优异的高温发射稳定性,具备胜任高温等苛刻服役环境的工作能力。n型和p型SiC纳米阵列室温至500℃的电子发射遵循传统F-N理论,其开启电场随温度的升高而降低,主要归因于SiC的功函数随温度升高而降低。
[Abstract]:Field emission is one of the inherent characteristics of low-dimensional nanomaterials. It has a wide application prospect in the fields of display and vacuum electronics. It is one of the frontier and hot spots in the international research. Silicon carbide (SiC) is the third generation wide band gap semiconductor with excellent mechanical properties, good chemical stability, low thermal expansion coefficient, high thermal conductivity and low electron affinity. It is one of the excellent candidate materials for field emission cathode. This paper aims at the research and development of field emission cathode material with excellent electron emission characteristics, through the exploration and optimization of technology. The growth and structure regulation of high directional SiC microtip nanoarrays are realized in order to integrate the local field enhancement effect, increase the electron emission point and doping control, and realize the cooperative enhancement of electron emission ability of SiC nanostructures. The preparation of single crystal SiC nanowires was realized by using catalyst assisted organic precursor pyrolysis process, using polysilane (PSN) as precursor to provide Si and C source for SiC growth, high purity Ar as protective atmosphere and carbon paper as substrate. N type and p type SiC nanowires were prepared by introducing dopants N and B respectively during pyrolysis. The key pyrolysis process parameters such as the type of substrate, the type of catalyst and the cooling rate were investigated and optimized. The growth and structural regulation of high directional SiC microtip nanoarrays were realized on 6H-SiC (0001) substrate. The field emission cathodes of n-type and p-type SiC microtip nanoarrays are fabricated. The results of field emission study show that the open electric field of n-type SiC microtip nanoarrays is 1.50V / 渭 m at room temperature, and when the temperature rises to 500 鈩，
本文编号：2347468
[Abstract]:Field emission is one of the inherent characteristics of low-dimensional nanomaterials. It has a wide application prospect in the fields of display and vacuum electronics. It is one of the frontier and hot spots in the international research. Silicon carbide (SiC) is the third generation wide band gap semiconductor with excellent mechanical properties, good chemical stability, low thermal expansion coefficient, high thermal conductivity and low electron affinity. It is one of the excellent candidate materials for field emission cathode. This paper aims at the research and development of field emission cathode material with excellent electron emission characteristics, through the exploration and optimization of technology. The growth and structure regulation of high directional SiC microtip nanoarrays are realized in order to integrate the local field enhancement effect, increase the electron emission point and doping control, and realize the cooperative enhancement of electron emission ability of SiC nanostructures. The preparation of single crystal SiC nanowires was realized by using catalyst assisted organic precursor pyrolysis process, using polysilane (PSN) as precursor to provide Si and C source for SiC growth, high purity Ar as protective atmosphere and carbon paper as substrate. N type and p type SiC nanowires were prepared by introducing dopants N and B respectively during pyrolysis. The key pyrolysis process parameters such as the type of substrate, the type of catalyst and the cooling rate were investigated and optimized. The growth and structural regulation of high directional SiC microtip nanoarrays were realized on 6H-SiC (0001) substrate. The field emission cathodes of n-type and p-type SiC microtip nanoarrays are fabricated. The results of field emission study show that the open electric field of n-type SiC microtip nanoarrays is 1.50V / 渭 m at room temperature, and when the temperature rises to 500 鈩，
本文编号：2347468
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