Study of high-brightness flat-panel lighting source using carbon-nanotube cathodeHigh density carbon nanotube field emitter arrays ͑CNT-FEAs͒ with various multilayer cathode structures have been fabricated on Si utilizing conventional integrated circuit technology and microwave-heated chemical vapor deposition process. The CNT-FEAs were configured as triode emitters with 1-µm thermal SiO 2 as the insulator and 400-nm Cr as the gate, and compared per the resulting morphologies, Raman spectra, and field emission characteristics. It was found that the Ni/ Cr/ Si cathode structure is the best fit for selective growth of CNTs in gate holes. In particular, a CNT-FEA fabricated on Ni͑60 nm͒ /Cr͑80 nm͒ / Si cathode structure has yielded excellent emission characteristics, with low turn-on and threshold fields, being, respectively, at 0.45 and 3.7 V / m. This triode CNT device also exhibited a uniform image of high brightness ͑ϳ1800 cd/ m 2 ͒ on a green-phosphor coated idium-tin-oxide glass and a relatively stable emission current, being tested at a constant anode voltage of 1000 and 900 V, respectively.