미세 팁 기판 위에 전기영동법으로 성장시킨 탄소 나노튜브의 전계방출 특성

Abstract

Field-emission characteristics of carbon nanotubes(CNTs), which were grown on conical-type tungsten micro-tips by using an electrophoretic deposition(EPD) method, were examined. The EPD method proved to be convenient to manipulate and arrange CNTs from well dispersed suspensions onto such tip-type substrates. The growth rate of CNTs was proportional to the applied d.c. bias voltage and the process time. It was observed from the Raman study that the EPD-produced CNTs showed better crystal qualities with the Raman intensity ratio(ID/IG) of 0.41-0.42 than the CVD-produced CNTs and their crystal qualities could be further improved by thermal annealing. The electron emitters based on the EPD-CNTs showed excellent field emission properties, such as the threshold voltage for electron emission of about 620V and the maximum emission current of about 345A. In addition, the EPD-CNTs exhibited the stable long-term(up to 40 h) emission capability and the emission stability was enhanced by thermal annealing.