Fabrication and properties of film-under-gate field emission arrays with SnO2 emitters for flat lamp

The film-under-gate field emission arrays (FEAs) have been fabricated on the glass substrates by conventional photolithography, anodic oxidation and lift-off method. SnO2 emitters were deposited on the cathode electrodes of under-gate triode by screen printing. The image of film-under-gate field emission arrays with SnO2 emitters was measured by the optical microscopy and field emission scanning electron microscopy (FESEM). The electric field distributions and electron trajectories of film-under-gate triode were simulated in the same anode voltage and different gate voltage by ANSYS. I–V characteristics of film-under-gate triode with SnO2 emitters were investigated. It indicated that the SnO2 emitters by screen printing uniformly distributed on the surface of cathode electrodes. The maximum anode current in this triode structure could come to 385 μA and the highest lightness was approximately 270 cd/m2 as the gate and anode voltage was 140 V and 2000 V, respectively, at the anode-cathode spacing of 1100 μm. Moreover, the emission current fluctuation was less than 5% for 8 h. It showed that the fabricated device has a good stability of field emission performance and long lifetime, which may lead to practical applications for field emission electron source based on flat lamp for back light units (BLUs) in liquid crystal display (LCD).