An improved planar-gate triode with CNTs field emitters by electrophoretic deposition

• Published in: Applied surface science 2011-02, Vol.257 (8), p.3259-3264
• Main Authors: Zhang, Y.A., Wu, C.X., Lin, J.Y., Lin, Z.X., Guo, T.L.
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Cathodes; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electric potential; Electrodes; Electrophoretic deposition; Emitters; Exact sciences and technology; Field emission; Gates (circuits); Physics; Planar-gate triode; Triodes; Voltage
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2010.10.153

▶ We have developed an electrophoretic process to selectively deposit CNTs emitters onto the surface of cathode electrodes and an improved planar-gate triode with CNTs field emitters has been successfully fabricated by conventional photolithography, screen printing and electrophoretic deposition and investigated its field emission characteristics. ▶ The experiment result showed that the CNTs emitters were selectively deposited cathode electrodes and each cathode electrodes had the uniform packing density. ▶ The field emission characteristics indicated that turn-on voltage of an improved planar-gate triode at current density of 1μA/cm2 was around 55V. ▶ When gate voltage was higher than turn-on voltage, the anode and gate current continually increased under the role of gate voltage. ▶ However, the increase ratio of gate current seemed to be higher than that of anode current as gate voltage was higher than 90V. ▶ Although the emission efficiency was modified from 94.8% to 54.9%, the emission image became brighter and the luminous image with dot matrix on the anode plate obviously increased with the increases of gate voltage from 0V to 100V with anode bias of 4000V and the anode–cathode spacing was about 2000μm. ▶ Moreover, the emission current fluctuation was smaller than 5% for 11h, which indicated that the fabricated device had a good field emission performance and long lifetime. ▶ In a word, this improved planar-gate triode with CNTs field emitters easily realizes the scan between gate and cathode electrodes in the drive circuit and presents the field emission image with dot matrix, which may lead to practical applications for dynamic back light unit and field emission displays. An improved planar-gate triode with carbon nanotubes (CNTs) field emitters has been successfully fabricated by conventional photolithography, screen printing and electrophoretic deposition (EPD). In this structure, cathode electrodes and ITO arrays linked with gate electrodes were interdigitated and paralleled on the same plane although the gate electrodes and cathode electrodes were isolated by dielectric layer, a so-called improved planar-gate triode structure. An electrophoretic process was developed to selectively deposit CNTs field emitters onto cathode electrodes in the CNTs suspension by an applied voltage between the gate electrodes and cathode electrodes. The optical microscopy and FESEM image showed that the CNTs emitters with the uniform packing density were selectively