Noise spectroscopy of localized states in Au/n-GaAs Schottky diodes containing InAs quantum dots

Localized states in Au/n-GaAs Schottky diodes, with InAs quantum dots (QDs) embedded in GaAs confining layers, were studied by means of low frequency noise measurements at temperatures ranging from 160 K to 299 K. Diodes containing a single array or three arrays of QDs were used; they all exhibited generation-recombination noise at low forward currents, which we attribute to local traps located in the GaAs layer. In the diode with a single array of QDs, a shallow trap level was detected with the activation energy about 0.037 eV, located above the Fermi level. In the diodes with three arrays of QDs we observed, in addition to the shallow level, a deep level located 0.1 eV below the midgap.