Low frequency noise in GaAs structures with embedded In(Ga)As quantum dots

Abstract

Current-voltage and low frequency excess electrical noise characteristics of two different-Schottky diode and n-i-n diode-GaAs structures embedded with self-assembled In(Ga)AS quantum dots are reported. We find the growth of quantum dots induces defects not only near the quantum dot but also extended to quite a distance toward the growth direction. In Schottky diode structure, comparing with the reference sample without the quantum dot layer, the current dependence of the low frequency noise spectral density indicated that the noise is from the generated interface states with the density increasing towards the band tail. Also the crystal quality of the Schottky diode including the quantum dot layer, deduced from the Hooge parameter, was slightly worse than that of the reference sample. For n-i-n diode structure, the current-voltage relation was linear, and a quadratic current dependence of the noise spectral density was observed. The Hooge parameter for the n-i-n structure was determined to be on the order of unity indicating the general degradation of the structure. (c) 2005 Elsevier B.V. All rights reserved.