Hexagonal boron nitride coated carbon nanotubes：interlayer polarization improved field emission

• Main Authors: Chang, Han Chen, 張瀚丞
• Other Authors: Hsu, Wen Kuang
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/67098999844193229908

博士 === 國立清華大學 === 材料科學工程學系 === 103 === 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.