Zhang Yongai

Synthesis and efficient field emission characteristics of patterned ZnO nanowires

Patterned ZnO nanowires were successfully synthesized on ITO electrodes deposited on the glass sub- strate by using a simple thermal evaporation approach. The morphology, crystallinity and optical properties of ZnO nanowires were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray and pho- toluminescence spectroscopy. Their field emission characteristics were also investigated. SEM images showed that the ZnO nanowires, with a diameter of 100-200 nm and length up to 5m, were highly uniform and well distributed on the linear ITO electrodes. The field emission measurement indicated that patterned ZnO nanowire arrays have a turn-on field of 1.6 V/ m at current density of 1 A/cm 2 and a threshold field of 4.92 V/m at current density of 1 mA/cm 2 at an emitter-anode gap of 700 m. The current density rapidly reached 2.26 mA/cm 2 at an applied field of 5.38 V/ m. The fluctuation of emission current was lower than 5% for 4.5 h. The low turn-on field, high current density and good stability of patterned ZnO nanowire arrays indicate that it is a promising candidate for field emission application.

Fabrication and field emission characteristics of a novel planar-gate electron source with patterned carbon nanotubes for backlight units

This paper describes the fabrication of backlight units (BLUs) for a liquid crystal display (LCD) based on a novel planar-gate electron source with patterned carbon nanotubes (CNTs) formed by electrophoretic deposition. The electric field distributions and electron trajectories of this triode structure are simulated according to Ansys software. The device structure is optimized by supporting numerical simulation. The field emission results show that the emission current depends strongly on the cathode-gate gap and the gate voltage. Direct observation of the luminous images on a phosphor screen reveals that the electron beams undergo a noticeable expansion along the lateral direction with increasing gate voltage, which is in good agreement with the simulation results. The luminous efficiency and luminance of the fabricated device reaches 49.1 lm/W and 5500 cd/m2, respectively. All results indicate that the novel planar-gate electron source with patterned CNTs may lead to practical applications for an electron source based on a flat lamp for BLUs in LCD.