The I–V characteristics of a 3D double-barrier resonant-tunneling structure is investigated to demonstrate the differences between coherent and sequential tunneling mechanisms. Increasing the ratio of phase-breaking scattering rate over tunneling broadening width from 0 to ∞, tunneling transport goes from the coherent to the sequential limit. In the first resonance region, I–V curve does not distinguish these two processes. In the second and higher resonance regimes, however, sequential tunneling current becomes appreciably larger than its coherent counterpart.
Broken Symmetry Effects due to Polarization on Resonant Tunneling Transport in Double-Barrier Nitride Heterostructures