This is a double barrier resonant tunneling diode in the GaAs/AlAs materials system with a modulation doped quantum well 136 Å wide near a 50 Å heterostructure quantum well. The N+ doping is 4x1018 1/cm3. This particular device has an asymmetric structure. The conduction band edge diagram shown to the right is not to scale.

The memory switching devices work because of the interplay between quantum interference between modulation and heterostructure quantum wells and space charge effects in the N+ region of the modulation doped quantum well resulting in multiple stable operating states each with a different I/V curve. This is a double barrier resonant tunneling diode in the GaAs/AlAs materials system with a modulation doped quantum well 136 Å wide near a 50 Å heterostructure quantum well. The AlAs barriers are approximately 1 ev The N+ doping is 4x1018 1/cm3. This particular device has an asymmetric structure.