Modeling and simulation of AlxGa/sub 1-x/N negative electron affinity cathodes

This work predicts the performance of negative electron affinity (NEA) cathodes fabricated with Al/sub x/Ga/sub 1-x/N material. A cathode of a given thickness is designed by specifying the compositional grading and the donor concentration as functions of position, based on available semiconductor data. Electrical operation of these cathodes was simulated by solving standard differential equations which describe semiconductor physics, using a fourth-order Runga-Kutta numerical analysis procedure. The J-V characteristics of the cathode in a vacuum diode were generated by computing the anode voltages corresponding to emitted current densities.