Three- versus two-dimensional electron gas injection in resonant tunnelling devices
The nature of a small precursor of resonance which appears in front of the main resonance peak in the currentvoltage characteristic of resonant-tunnelling devices based on GaAs/AlGaAs double-barrier heterostructures is studied. The competition between the precursor and main-peak current is examined within the temperature range 2400 K and under a magnetic field up to 13 T. The precursor is interpreted as the contribution to resonant tunnelling of ballistic electrons injected from a three-dimensional electron gas in the emitter region. Instead, the main resonance peak is due to the electron injection from a two-dimensional electron gas in a triangular well formed under bias in the emitter spacer layer.
resonant tunnelling heterostructures semiconductors low dimensional transport