Long lifetime emission from screen printing carbon nanotubes over 45,000 h at 1.27 mA/cm2 with 10% duty ratio

Abstract

A long time operation of field electron emission over 45,000h was achieved using the screen printing carbon nanotube (CNT) emitter fabricated on an ITO coated glass substrate. The measurement was carried out in an ultra-high vacuum chamber at around 3×10−7Pa in pressure with continuously applying voltage of rectangular pulses at 743V or 730V peak, 60Hz frequency and 10% duty ratio. The emission current corresponding to the voltage pulse at 1.27mA/cm2 density was repeatedly and reproducibly observed for more than 5years. Because the operated condition was 10 times higher at the current density than that of the conventionally developed field emission lamps (FELs), the expected lifetime of the presented emitter will be 450,000h though the vacuum level of the measurement was extremely higher than that of the actual operation of FELs. By investigating the morphology of the emitter after terminating the operation, it was found that sparse bundles of agglomerated CNTs were standing in the long lifetime CNT emitter.