表面鍍覆六方晶系氮化硼之奈米碳管:界面極化強化場發射特性

奈米碳管具有高機械強度、強化學穩定性、高長徑比與場增強因子等特性，相當適合作為場發射之發射體。在本文中，我們將奈米碳管鍍覆上六方晶系之氮化硼，使界面處產生極化現象使得電子分別坐落於氮原子及碳原子處，且在氮化硼和奈米碳管間產生一電場，此電場會幫助電子穿越氮化硼和奈米碳管之界面處然後由氮的電子填滿帶及硼的電子未填滿帶射出。鍍有氮化硼之奈米碳管之場發射電流密度具有更高的穩定性，其波動程度在4%之內。文中量測到之起始電場由奈米碳管的6.51 V/μm變成鍍完氮化硼後的2.65-2.67 V/μm；臨界電場由9.82 V/μm變為4.41-4.43 V/μm。

關鍵字

奈米碳管；場發射；氮化硼；界面極化

並列摘要

Carbon nanotubes (CNTs) which have high mechanical strength, chemical stability, aspect ratio, and field enhancement factor (β) are considered as ideal field emitters. In this thesis, coating of h-BN onto carbon nanotubes induces polarization at interfaces and charges become localized at N and C atoms respectively. Field emission of coated tubes is found to be highly stable and current density fluctuates within 4%. Study further reveals that electric field established between coatings and tubes facilitates charge transfer across interfaces and electrons are emitted through occupied and unoccupied bands of N and B atoms. Measurements give turn on field = 6.51 V/μm for CNTs and 2.65-2.67 V/μm for coated tubes; the threshold field being measured to be 9.82 V/μm and 4.41-4.43 V/μm respectively.

並列關鍵字

Carbon nanotube ； Field emission ； Boron nitride ； Interlayer polarization

參考文獻

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表面鍍覆六方晶系氮化硼之奈米碳管:界面極化強化場發射特性

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