Shot noise in self-assembled InAs quantum dots

We investigate the noise properties of a GaAs-AlAs-GaAs tunneling structure with embedded self-assembled InAs quantum dots in the single-electron tunneling regime. We analyze the dependence of the relative noise amplitude of the shot noise on bias voltage. We observe a non-monotonic behaviour of the Fano-factor $\alpha$ with an average value of $\alpha \approx 0.8$ consistent with the asymmetry of the tunneling barriers. Reproducible fluctuations observed in $\alpha$ can be attributed to the successive participation of more and more InAs quantum dots in the tunneling current.