Resonant-tunneling diode
![A working mechanism of a resonant tunneling diode device and negative differential resistance in output characteristic. There is a negative resistance characteristic after the first current peak, due to a reduction of the first energy level below the source Fermi level with gate bias. (Left: band diagram; Center: transmission coefficient; Right: current–voltage characteristics). The negative resistance behavior shown in right figure is caused by relative position of confined state to source Fermi level and bandgap.](/Images/godic/202502/07/Rtd_seq_v33743.gif")
![A double-barrier potential profile with a particle incident from left with energy less than the barrier height.](/Images/godic/202502/07/Double_square_barrier_potential3743.png")
![Typical structure of a Si/SiGe resonant interband tunneling diode](/Images/godic/202502/07/SiGe-RITD-typical-structure3743.jpg")
![Band diagram of a typical
Si/SiGe resonant interband tunneling diode calculated by
Gregory Snider's 1D Poisson/Schrödinger Solver.](/Images/godic/202502/07/SiGe-RITD-typical-banddiagram3743.jpg")
A resonant-tunneling diode (RTD) is a diode with a resonant-tunneling structure in which electrons can tunnel through some resonant states at certain energy levels. The current–voltage characteristic often exhibits negative differential resistance regions.