Giant temperature resonances of noise in submicron quantum well structures

We show that excess noise in micron-sized samples fabricated from Si-doped GaAs/GaAlAs quantum wells and heterostructures is a strong non-monotonic function of temperature with several sharp peaks below room temperature. The noise power at the peaks exceeds the background noise by several orders of magnitude. The observed behaviour represents a classical noise source where only a single type of switching defect with a well-defined activation energy is present. We attribute the resonances to deep metastable donors and provisionally identify one of the donors as the known DX-centre in GaAs and GaAlAs. © 1994.