Diodes employing one or more Group III-Nitride polarization junctions. A III-N polarization junction may include two III-N material layers having opposite crystal polarities. The opposing polarities may induce a two-dimensional charge sheet (e.g., 2D electron gas) within each of the two III-N material layers. Opposing crystal polarities may be induced through introduction of an intervening layer between two III-N material layers. The intervening layer may be of a material other than a Group III-Nitride. Where a P-i-N diode structure includes two Group III-Nitride polarization junctions, opposing crystal polarities at a first of such junctions may induce a 2D electron gas (2DEG), while opposing crystal polarities at a second of such junctions may induce a 2D hole gas (2DHG). Diode terminals may then couple to each of the 2DEG and 2DHG.