Theory and design of semiconductor electron-wave interference filter/emitters

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Abstract
A voltage‐biased semiconductor superlattice structure is designed to operate simultaneously as a continuously voltage‐tunable, electron interference filter and as an electron emitter. Using the analogies between electromagnetic waves and electron de Broglie waves, a systematic procedure for designing the quantum wells and barriers comprising the electron‐wave filter/emitter superlattice is developed. A generalized procedure for analyzing the electron‐current transmittance and reflectance spectral responses of these superlattice structures is then presented. A practical, continuously tunable filter/emitter consisting of multiple layers of Ga1−xAlxAs (compositional superlattice) is designed to emit nearly monoenergetic 0.20‐eV electrons by appropriate selection of the layer compositions and thicknesses. The constraints required to have thicknesses that are integer multiples of the monolayer thickness and to avoid phonon scattering of electrons into the L band are included. The filter/emitter is shown to have a wide tunable energy range. A sensitivity analysis of the device characteristics in the presence of fabrication errors reveals a very stable device response. Such quantum electron‐wave devices could serve as continuously tunable hot‐electron emitters in ballistic transistors and in future guided electron‐wave integrated circuits.