Transparent field emitters with light reflector

Carbon nanotube (CNT) network based on single-walled CNT is adopted for transparent field emitters (TFEs). TFEs play roles of electrode as well as field emitters at the same time. CNT network is prepared by the spray coating method and CNTs in the network are vertically aligned for field emitters by the triboelectricity method [1]. It shows a low threshold field of 1.7 V/μm corresponding to the current density of 10 μA/cm2 and stable lifetime performance. A diode-type field emission device is prepared by using TFEs. Transparency of TFE cathode allows an inverted design [2] of a diode-type field emission device, where light comes out not from an anode side as in a conventional design but from a cathode side. Therefore, light reflector can be installed on the anode side below a phosphor layer replacing a transparent electrode such as indium tin oxide (ITO), which enhances illuminance of the device. The diode-type field emission device composed of the present TFEs and an aluminum light reflector shows 35% higher efficiency of illuminance than the conventional device. Therefore, TFEs with light reflector have a strong potential in field emission devices.