Current–voltage and noise characteristics of reverse-biased Au/n-GaAs Schottky diodes with embedded InAs quantum dots

Abstract

Schottky contacts on n-type GaAs with embedded InAs quantum dots (QDs) were studied by current-voltage (I-V) and low-frequency noise measurements. For comparison, diodes not containing QDs were investigated as reference devices. A wide distribution of the ideality factor was observed, correlated with the level of the leakage current. Reverse I-V characteristics on the logarithmic scale indicate that the space-charge limited current dominates the carrier transport in these diodes. In all diodes, the reverse current noise spectra show 1/f behaviour, attributed to traps uniformly distributed in energy within the band-gap of the GaAs capping layer. Depth profiling measurements of the 1/f noise power spectral density demonstrate the impact of the QDs on these traps. In diodes containing QDs, in addition to the 1/f noise, a generation-recombination noise is found originating from a deep trap level localized in the vicinity of the QD plane.

Rapid thermal annealing temperature dependence of noise properties in Au/n‐GaAs Schottky diodes with embedded InAs quantum dots in asymmetric In0.2Ga0.8As wells

“…The leakage current conduction mechanism has been attributed to space charge limited current, correlated to a distribution of trapping centers in the forbidden energy gap of the capping GaAs layer [14]. The experimental data of Fig.…”

“…The 1/f noise has been attributed to traps uniformly distributed in energy within the band-gap of the GaAs capping layer [14]. The normalized spectral densities S 1/f /I 2 as a function of the depletion region width W, measured at the frequency of f = 10 Hz are shown in Fig.…”

Ideality factor dependence of capacitance and reverse current noise in Au/n‐GaAs Schottky diodes with embedded self‐assembled InAs quantum dots

“…All diodes were from the same wafer. The observed dispersion of the ideality factors is attributed to contact inhomogeneities that confine the diode current to small parts of the contact areas, resulting in an effective Schottky contact area which varies from diode to diode [7]. The experimental data of Fig.…”

“…After the formation of QDs, a 10nm thick capping layer of undoped GaAs was deposited by MBE, followed by an upper GaAs layer of thickness 0.4 µm with electron concentration 2×10 16 cm -3 . Details on the growth procedures are presented elsewhere [7]. After the growth, rapid thermal annealing was performed at 700 o C The trap properties of Au/n-GaAs Schottky diodes with embedded InAs quantum dots (QDs) and different ideality factors were studied by capacitance-voltage (C-V) and lowfrequency noise (LFN) measurements in the reverse bias regime.…”

“…The effect of self-assembled InAs QDs in Au/n-GaAs Schottky diodes was studied in previous investigation [7]. In this work, we investigate in detail the trap properties of Au/n-GaAs Schottky diodes with embedded QDs in terms of the ideality factor, in order to correlate the Schottky contact performance with the QDs trap properties.…”