Low-frequency noise properties of beryllium δ-doped GaAs/AlAs quantum wells near the Mott transition

Noise properties of beryllium delta-doped GaAs/AlAs multiple quantum wells, doped both above and below the Mott transition, are studied within the frequency range of 10 Hz−20 kHz and at temperature from 77 K to 350 K. It is shown that the generation-recombination noise in structures close to the Mott transition exhibits two peaks—a frequency and temperature-dependent peak between 120 and 180 K and a broadband, frequency- and temperature- nearly independent peak around 270 K. Activation energies are estimated; origin of the broadband maximum is attributed to holes tunnelling into defect trap states located in the AlAs barrier/GaAs quantum well interface.