Zener Tunneling. In a semiconductor, an electric field (if it’s large enough) can produce transitions between energy bands—a phenomenon known as Zener tunneling. A uniform electric field E = -E₀î,, for which

makes the energy bands position dependent, as shown in Figure 9.7. It is then possible for an electron to tunnel from the valence (lower) band to the conduction (upper) band; this phenomenon is the basis for the Zener diode. Treating the gap as a potential barrier through which the electron may tunnel, find the tunneling probability in terms of E_g and E₀ (as well as m, ћ, e).

Figure 9.7: (a) The energy bands in the absence of an electric field. (b) In the presence of an electric field an electron can tunnel between the energy bands.

Transcribed Image Text:

H' = -eEox,