High magnetic field tunneling transport in a double quantum well-triple barrier resonant tunneling diode

Abstract

We have measured the magnetotransport of double GaAs quantum well-triple AlAs barrier resonant tunneling heterostructures in pulsed magnetic fields up to 48 T, and temperatures down to 0.3 K. The tunneling structure is designed for a near-simultaneous (triple) resonance, under bias, of the quantum well energy levels and the lowest quasi-2D emitter state. The fan chart of the I( V) resonances is more complex than that of a single quantum well since both emitter-well and well-well transitions can occur, which can be discriminated by voltage dependence. In addition to transitions corresponding to the emission of an LO phonon, we also observe at high field a transition which may correspond to the absorption of an LO phonon (emitter-well). Shubnikov-de Haas oscillations in the tunnel current of all resonances are observed. At the near-triple resonance, corresponding to a populated 2D well density of n s= 4.5 × 10 11 cm −2, a SdH peak (at 0.3 K) is observed at 29 T, assigned to a Landau level filling factor of 2 3 . This peak weakens by 2 K, whereas the integer filling factor peaks are unchanged with temperature.