질화탄소 표면층 및 열처리가 탄소 나노튜브 미세팁의 전계방출 및 장시간 안정성에 미치는 영향

Abstract

The effects of thermal treatment on CNTs, which were coated with a-CNx thin film, were investigated and related to variations of chemical bonding and morphologies of CNTs and also properties of field emission induced by thermal treatment. CNTs were directly grown on nano-sized conical-type tungsten tips via the inductively coupled plasma-chemical vapor deposition (ICP-CVD) system, and a-CNx films were coated on the CNTs using an RF magnetron sputtering system. Thermal treatment on a-CNx coated CNT-emitters was performed using a rapid thermal annealing (RTA) system by varying temperature (300-700ºC). Morphologies and microstructures of a-CNx/CNTs hetero-structured emitters were analyzed by FESEM and HRTEM. Chemical composition and atomic bonding structures were analyzed by EDX, Raman spectroscopy, and XPS. The field emission properties of the a-CNx/CNTs hetero-structured emitters were measured using a high vacuum (below 10-7 Torr) field-emission measurement system. For characterization of emission stability, the fluctuation and degradation of the emission current were monitored in terms of operation time. The results were compared with a-CNx coated CNT-emitters that were not thermally heated as well as with the conventional non-coated CNT-emitters.