7. A Resonance Diode
So our goal has been to create a diode whose functionality depended on tunneling. A diode is essentially a current switch. We are now ready to propose a possible device. Remember the resonance energy of a double barrier and how peaked the resonance was. Suppose it were possible to shift the resonance energy at will. Then we could send electrons at a particular energy and shift the resonance of the double barrier to align if we want the diode on, and misalign if we want the diode off. This device is called a resonant tunneling diode.
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| Figure 9: Resonant Tunneling Diode |
The device in Figure 9 works by aligning the resonant energy of the double barrier with the incoming electrons by applying a voltage drop over the active region. An interesting application of this device would be to spin selection. Consider a RTD that has the inner region magnetized (Figure 10). Then the resonant energy level would split into two levels depending on the electron spin. Aligning the barrier to match either spin up or spin down you could skew the population of spins however you wish.
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| Figure 10: Spin Selecting Resonant Tunneling Diode |
Continue to see some fun movies of RTDs.