III-Nitride Tunnel Junctions and Their Applications

Interband tunneling in semiconductors [1, 2] is one of the clearest manifestations of quantum mechanics in electronic devices. In the case of interband tunneling in a heavily doped PN junction, in reverse bias, electrons tunnel from the filled states in the valence band to the empty states in the conduction band. Under forward bias, tunneling current is observed when electrons tunnel from filled states in the conduction band to empty states in the valence band, as shown in Fig. 8.1. As the conduction band on the n-side becomes biased higher in energy than the valence band, states are not available for electrons to tunnel into. As a result, the current decreases, leading to a characteristic negative differential resistance regime.