Fabrication and characterization of a monolithic thin-film edge emitter device with zinc–oxide–tungsten-based thin-film phosphor

Abstract

Advanced applications, such as space and geophysical exploration, medical and military applications, transportation and communications industries, and the goal of hang-on-the-wall television and computer monitors, have driven display technology toward a rapid advancement and development of the flat panel display (FPD) industry. Displays based on the principles of field emission have been regarded as a technology with a potential of replacing cathode ray tubes (CRTs) and liquid crystal displays. A field-emission display (FED) combines the best performance of a CRT in a configuration of a FPD because a FED offers high-power efficiency, high brightness and resolution, wide viewing angles, light weight, tolerance to temperature changes, and instant-on operation. However, commercial application of FEDs has been delayed because of the complex submicron processing involved in the fabrication of microtips for the cathode, early failure of cathodes due to sputter damage from uncontrolled emission current or current runoff, nonavailability of blue phosphors operating in low-voltage regimes, and lack of optimum sealing conditions. This article summarizes the development of a monochromatic monolithic thin-film edge emitter (MT-FEE) device while implementing a thin-film blue-light-emitting phosphor of zinc oxide and tungsten (ZnO:W). The device design reported here overcomes some of the above mentioned drawbacks of conventional FED designs. Performance of the MT-FEE devices was judged by controlling key parameters associated with the technology. Several test structures were fabricated by varying the dielectric, separating anode and cathode lines, in a range of 3–6 μm with emitter configurations as either saw-tooth or rectangular wedges to establish performance of the devices. Stable emission current of an approximate value of 200 nA per pixel was obtained at 300 V for 3 μm devices. Blue light was visible to the naked eye from several excited pixels in the 3 μm devices at voltages as low as 270 V.