Publications Repository  HelmholtzZentrum DresdenRossendorf
Measurements of nonGaussian noise in quantum wells
Ben Simon, A.; Paltiel, Y.; Jung, G.; Berger, V.; Schneider, H.
Gaussian generationrecombination is known to be a dominant mechanism of current noise in quantum well systems biased by electric field normal to the layers. We have found pronouncedly nonGaussian excess current noise in ntype and ptype multiple quantum wells. The nonGaussian noise has been attributed to metastable spatial configurations of electric field. The metastability is likely originating from negative differential conductance caused by intervalley scattering in ntype wells and heavy and light holes tunneling in ptype wells. At a constant bias the quantum well system randomly switches between a high resistivity state with low current flow and low resistive state with high current flow. The nonGaussianity of the noise is more pronounced in ptype wells where the time traces of current fluctuations resemble closely twolevel random telegraph signal which has not been straightforwardly observed in ntype wells. The nonGaussian character of the noise in ntype systems has been revealed by measurements of nonzero skewness of the amplitude distributions. The difference between noise properties of n and ptype systems has been attributed to small capture probability of electrons in ntype wells, as opposed to very high capture probability of holes in ptype wells. As a consequence the noise of any ptype multiwell system is dominated by fluctuations of a single while in the ntype the noise appears as a superposition of many fluctuators associated with individual wells.
Keywords: generationrecombination noise; random telegraph noise; skewness; GaAs/AlGaAs; quantum well

Physical Review B 76(2007), 23530812353089
DOI: 10.1103/PhysRevB.76.235308
Cited 6 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ10585
Publ.Id: 10585