Current crowding effects in a CdS/LaS cold cathode

Abstract

We analyze the importance of current crowding in a new cold cathode emitter that consists of a thin wide band-gap semiconductor material sandwiched between a metallic contact and a low work function semimetallic thin film. Potential material candidates are suggested to achieve low-voltage (<10 V), room-temperature cold cathode operation with emission currents of several tens of A/cm2. We calculate the lateral potential drop that occurs across the emission window of cold cathodes with rectangular geometry and describe its effects on the emitted current density profile. The power dissipation in the cold cathode is calculated as a function of a dimensionless parameter characterizing the importance of current crowding. We determine the range of dc bias over which cold cathodes of different width must be operated to minimize current crowding effects.