Negative Resistance Characteristics Of Surface Conduction Electron Emission Display Device

Compared with other flat-panel display (LCD/PDP), surface conduction electron emission display device (SED) has obvious advantages in energy consumption, resolution, perspective. But, the emission efficiency and life of cathode hinder the development of surface conduction electron emission display device. Some researchers found that the device’s conduction current and voltage present repeat voltage-controlled negative resistance (VCNR) phenomenon when it was electric formed in vacuum. The phenomenon of VCNR has a certain relationship with the device’s emission current (no VCNR, no emission current). Thus there was an urgent need to reveal the formation mechanism of VCNR. Then clarified the relationship which was about VCNR and the inherent law of electron emission characteristics. Based on it, more excellent performance devices could be made. In this paper particle film AlN/Al would be choose as cathode material of surface conduction electron emission display device. Then electric formed it in vacuum, studied the phenomenon of VCNR and its mechanism.Magnetron sputtering and lithography technology were chosen to prepare device whose cathode material was AlN/Al. The electric formation times, the preparation method of cathode material, device structure, electric forming environment, applied electric field and granular membrane material composition were taken into consideration if they had affects on the electrical characteristics of the device. According to the evolution law of electrical properties, discuss the electron emission mechanism and the device’s VCNR, following conclusions could be got:The different electrical environment’s influence on VCNR was studied. Experiments showed that the device’s curve of Ⅰ-Ⅴ presented differently when they were loaded the same voltage under low vacuum and high vacuum. Under low vacuum, the device of the conduction current became as large as current source limit and the VCNR phenomenon couldn’t be repeated. And conduction current changed violently then formed a wide slit (much larger than 2 μ m) in thin film cathode. Under high vacuum, device conduction current was stable and VCNR could be repeated. At last, formed a slit as wide as 952nm in the granular membrane.The different applied electric field models’ affect on device’s electrical characteristics was studied. The devices were loaded different voltages (+5V, OV,-5V). It was found that the device which was loaded-5 V, VCNR phenomenon was more obvious. The emission current and the emission efficiency increased. On the contrary, emission current and the emission efficiency of the device dropped when it was loaded+5V.The influences of different device structure on the electrical properties was studied. Two type devices were prepared:Device 1 (prepare copper electrode first and then emission cathode), Device 2(prepare emission cathode first and then copper electrode). Experiments showed that the former’s conduction current was smaller and the device’s voltage was larger than the later when the phenomenon of VCNR appeared. The former’s conduction current was more stable and formed a slit which was suitable for surface electron emission.The influences of material composition on the device electrical characteristics was studied. Under the premise of N2:Ar=3:90sccm, two different properties of particles whose working air pressure are 0.85Pa and 1Pa were prepared by magnetron sputtering. Experiment showed that the particles prepared under 0.85Pa had good electrical conductivity. But its conduction current was too large to form an ideal slit. And its VCNR appeared earlier than the particles prepared under 1Pa. On the contrary, the latter’s conduction current was more stable and formed an ideal slit. And also it had good emission current.After electric forming, the change of membrane element content was studied by Scanning electron microscope X-ray microanalysis (SEM-EDS). And found that A1 element was changed and the content increased by 4.29%.Combine with macro electrical characteristics and the change of particle film, it is can be sure that the content of conductive elements A1 in particle film has a direct contact with VCNR.