Enhanced shot noise in tunneling through coupled self‐assembled InAs quantum dots

Abstract

AbstractWe present measurements of the shot noise of vertically coupled self‐assembled InAs quantum dots (QDs) and find a surprising enhancement with a distinct double‐peak structure.1By applying an external bias voltage we observe pronounced peaks in the dc current–voltage characteristics that correspond to electron transport through a stack of vertically coupled QDs. At these peaks we find enhanced shot noise in contrast to suppressed shot noise at a single layer of QDs.To characterize the measured shot noise S the so‐called Fano factor α is introduced. At both sides of the current peak the Fano factor α rises to values up to 1.4, whereas the noise is reduced on top of the peak (α < 1). We discuss qualitative agreement with a theoretical model which predict such a super‐Poissonian shot noise. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)