Bistability Characteristics of GaN/AlN Resonant Tunneling Diodes Caused by Intersubband Transition and Electron Accumulation in Quantum Well

The bistability characteristics of GaN/AlN resonant tunneling diodes (RTDs) grown on a sapphire substrate were investigated. The RTDs exhibit bistability characteristics with high and low resistivity switched by varying the polarity of the bias voltage. Negative differential resistance is realized in the current-voltage (I-V) characteristics after low resistivity is achieved by application of a negative bias. The calculated I-V characteristics based on self-consistent methods indicate that the bistability characteristics are caused by the accumulation of electrons in the quantum well due to intersubband transitions. Also, the bistability characteristics of GaN/AlN RTDs were discussed toward the application to the ultrafast nonvolatile memory.