Electrical properties of GaAs Schottky diodes with embedded InAs self-assembled quantum dots

The electrical properties of InAs self-assembled quantum dots (QDs), embedded in GaAs are investigated by low-frequency noise measurements using Au/n-GaAs Shottky diodes as a test device. The I-V characteristic deviates from the thermionic-emission diffusion theory showing an excess current in the low current region. The noise spectra show a 1/f-like behavior at frequencies up to 100 Hz and 1/f² behavior at higher frequencies. After decomposition of the different types of noise, from the g-r noise parameters we obtain the time constant and their density N_T of the single energy traps lying in the bulk of the n-GaAs capping layer. For the 1/f noise, the current spectral density is proportional to 1F² at low currents and proportional to IF for higher currents. The noise data are restricted in the current region where there is no influence of the series resistance of the diode. The 1/f noise data originating from interface states between the metal and n-GaAs capping layer, are analyzed.