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.