The effect of the electron energy spectrum on electronic efficiency and power in thermionic and thermoelectric devices

Abstract

We show that the details of the energy spectrum of transmitted electrons in thermionic and thermoelectric devices have a significant impact on their performance. We distinguish between traditional thermionic devices where electron momentum is filtered in the direction of transport only and a second type, in which the electron filtering occurs according to total electron momentum. Our main result is that the electronic efficiency of a device is not only improved by reducing the width of the transmission filter, but also strongly depends on whether the transmission probability rises sharply from zero to full transmission. Finally, we comment on the implications of the effect the shape of the electron energy spectrum has on the efficiency of thermoelectric devices and suggest an experimental measure for providing insight into the nature of the electron energy spectrum.