Investigation of single electron traps induced by InAs quantum dots embedded in GaAs layer using the low-frequency noise technique

The properties of the traps induced by InAs quantum dots (QDs), embedded in a GaAs layer grown by molecular beam epitaxy, are investigated by the low-frequency noise measurements using the Au/n-GaAs Schottky diode as a test device. The forward current noise spectra are composed of two noise components: a 1/f-like noise at low frequencies and a generation-recombination (g-r) noise at higher frequencies. The 1/f noise is ascribed to the mobility fluctuations within the space-charge region. The obtained Hooge parameter (α_H=6×10^-5) is larger than the expected value considering the phonon or impurity scattering mechanism, indicating the presence of the defects associated with QDs. The analysis of the g-r noise gives a single trap of density of about 1.6×10¹⁴ cm^-3 in the part of the GaAs layer located above the QDs.