Voltage noise in an AlxGa1−xAs-GaAs heterostructure

Voltage noise in an heterostructure consisting of a Si-doped Al0.34Ga0.66As layer grown on a not-intentionally doped GaAs layer was investigated in the temperature range 80–330 K and in the frequency range of 1 Hz–100 kHz. The noise consisted of three types: thermal noise, which is independent of the frequency, 1/f-noise, and generation-recombination noise. The generation-recombination noise is associated with trapping and detrapping of charge carriers. The relaxation times show thermally activated behavior, and the activation energies obtained from Arrhenius plots are 810±20, 400±30, and 235±17 meV. These data are compared with those obtained from relatively thick AlxGa1−xAs layers.