  The large electronic polarization in III-V nitrides allow for novel physics
not possible in other semiconductor families. In this work, interband Zener
tunneling in wide-bandgap GaN heterojunctions is demonstrated by using
polarization-induced electric fields. The resulting tunnel diodes are more
conductive under reverse bias, which has applications for zero-bias
rectification and mm-wave imaging. Since interband tunneling is traditionally
prohibitive in wide-bandgap semiconductors, these polarization-induced
structures and their variants can enable a number of devices such as
multijunction solar cells that can operate under elevated temperatures and high
fields.
