SINGLE INSULATING THIN-FILM COLD-CATHODE USING HOT-ELECTRONS IN II-IV COMPOUNDS

A new thin-film cold cathode (TFCC) with the structure: glass substrate/ITO electrode/Ta2O5/ZnS or SrS/Au electrode, has been investigated. The TFCC uses hot electrons produced in ZnS or SrS layer by a high field, and the device produces planar and pulsated emission. It is estimated that the electrons contributing to the emission in the ZnS and SrS must have energies of more than about 2.7 eV. The average emission currents for the ZnS- and SrS-based TFCCs were about 28 nA/cm2 and about 43 nA/cm2, respectively, when the devices were driven with a 5 kHz sinusoidal voltage. Cathodoluminescence was also observed with the ZnS-based device driven at 5 kHz, and the luminances were about 160 cd/m2 for a green emitting ZnO:Zn phosphor, and about 85 cd/m2 for a blue emitting ZnS:Ag phosphor.