【摘要】：場發(fā)射是低維納米材料的固有特性之一,在顯示和真空電子等領(lǐng)域具有廣泛的應(yīng)用前景,是當(dāng)前國際研究的前沿和熱點(diǎn)之一。碳化硅(SiC)是第三代寬帶隙半導(dǎo)體,具有優(yōu)異的力學(xué)性能、良好的化學(xué)穩(wěn)定性、低熱膨脹系數(shù)、高熱導(dǎo)率和低電子親和勢(shì),是場發(fā)射陰極的優(yōu)異候選材料之一本論文工作以具有優(yōu)異電子發(fā)射特性的場發(fā)射陰極材料研發(fā)為目標(biāo),通過工藝的探索和優(yōu)化,實(shí)現(xiàn)高定向SiC微尖納米陣列的生長及其結(jié)構(gòu)調(diào)控,以期集局域場增強(qiáng)效應(yīng)、增加電子發(fā)射點(diǎn)和摻雜調(diào)控三種方法于一體,實(shí)現(xiàn)SiC納米結(jié)構(gòu)的電子發(fā)射能力的協(xié)同強(qiáng)化。采用催化劑輔助有機(jī)前驅(qū)體熱解工藝,以聚硅氮烷(PSN)為前驅(qū)體提供生長SiC所需的Si源和C源、高純Ar為保護(hù)氣氛、碳紙為生長襯底,實(shí)現(xiàn)單晶SiC納米線的制備；在熱解過程中引入摻雜劑N和B分別實(shí)現(xiàn)n型和p型SiC納米線的制備；并對(duì)關(guān)鍵熱解工藝參數(shù)如襯底種類、催化劑種類和降溫速率進(jìn)行探索和優(yōu)化,在6H-SiC(0001)襯底上實(shí)現(xiàn)了高定向SiC微尖納米陣列結(jié)構(gòu)的生長及其結(jié)構(gòu)調(diào)控。實(shí)現(xiàn)高定向n型和p型SiC微尖納米陣列場發(fā)射陰極的制備,場發(fā)射研究結(jié)果表明,n型SiC微尖納米陣列室溫下的開啟電場為1.50 V/μm,當(dāng)溫度升至500℃時(shí),其開啟電場降至0.94 V/0μm,表明實(shí)驗(yàn)制備的SiC場發(fā)射陰極材料具有優(yōu)異的場致電子發(fā)射能力；調(diào)控SiC納米陣列的密度并研究陣列密度對(duì)其場發(fā)射性能的影響,采用不同厚度的催化劑Au膜50、70和90 nm,獲得密度分別為～2.9×107、-4.0×107和～5.7× 107根/cm2的SiC納米陣列,其開啟電場分別為～1.79、-1.57和～1.95 V/μm,說明合理密度的納米陣列可增加場發(fā)射點(diǎn)的數(shù)量和限制場屏蔽效應(yīng)有利于提高其場發(fā)射性能;p型SiC微尖納米陣列室溫下的開啟電場為1.92 V/gm,當(dāng)溫度升至500℃時(shí),其開啟電場降至0.98 V/μm.在室溫和200℃下,p型SiC微尖納米陣列發(fā)射電流密度波動(dòng)分別為6.5%和7.8%,表明B摻雜的SiC微尖納米陣列結(jié)構(gòu)具有優(yōu)異的高溫發(fā)射穩(wěn)定性,具備勝任高溫等苛刻服役環(huán)境的工作能力。n型和p型SiC納米陣列室溫至500℃的電子發(fā)射遵循傳統(tǒng)F-N理論,其開啟電場隨溫度的升高而降低,主要?dú)w因于SiC的功函數(shù)隨溫度升高而降低。
[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，

本文編號(hào)：2347468