Magneto-optical investigation of two-dimensional gases in n-type resonant tunneling diodes

Abstract

We have studied the polarized emission from the contact layers and the quantum well of asymmetric n-type GaAs/GaAlAs resonant tunneling diodes under high magnetic fields (up to 19 T) parallel to the tunnel current. The photoluminescence from the GaAs contact layers shows evidence of the recombination from a two-dimensional hole gas accumulated next to the GaAlAs barrier and free carriers. Both the energy position and the intensity of this emission are voltage dependent. In addition, the photoluminescence from the two-dimensional hole gas and quantum well is strongly spin-polarized under the applied voltage and high magnetic fields. Pronounced oscillatory features are observed in the magnetic field dependence of the polarization degree from the quantum well and the two-dimensional hole emissions at integer filling factors. The obtained data show that resonant tunneling diodes are interesting systems to study the physical properties of voltage-controlled two-dimensional gases in the accumulation layers and quantum well.