Samsung SDI Co., Ltd. (Yeongtong-gu, Suwon-si, Gyeonggi-do, KR) earned U.S. Patent 7,744,440 for a method of growing carbon nanotubes and a method of manufacturing a field emission device using the carbon nanotubes.
Inventors Ha-Jin Kim and Sang-Mock Lee developed a method of growing carbon nanotubes that includes steps of preparing a substrate, forming a catalyst metal layer on the substrate to promote growing of carbon nanotubes, forming an inactivation layer on the catalyst metal layer to reduce the activity of the catalyst metal layer, and growing carbon nanotubes on a surface of the catalyst metal layer. Because the inactivation layer partially covers the catalyst metal layer, carbon nanotubes are grown on a portion of the catalyst metal layer that is not covered by the inactivation layer. Thus, density of the carbon nanotubes can be controlled. This method for growing carbon nanotubes can be used to make an emitter of a field emission device. The field emission device having carbon nanotube emitter made of this method has superior electron emission characteristics.
FIG. 6A shows scanning electron microscope (SEM) images of carbon nanotube emitters of a field emission device formed by a CVD method according to the principles of the present invention; and
FIG. 6B shows SEM images of carbon nanotube emitters of a field emission device formed by a conventional CVD method as a comparative example.
Samsung’s method of growing carbon nanotubes is able to control the density of the carbon nanotubes.d. Also, Samsung provides a method of manufacturing a field emission device that has superior electron emission characteristics by controlling the density of a carbon nanotubes of the emitter, thereby reducing the driving voltage and increasing the field emission current.