Detection of charge motion in a non-metallic silicon isolated double quantum dot

Abstract

As semiconductor device dimensions are reduced to the nanometer scale,\neffects of high defect density surfaces on the transport properties become\nimportant to the extent that the metallic character that prevails in large and\nhighly doped structures is lost and the use of quantum dots for charge sensing\nbecomes complex. Here we have investigated the mechanism behind the detection\nof electron motion inside an electrically isolated double quantum dot that is\ncapacitively coupled to a single electron transistor, both fabricated from\nhighly phosphorous doped silicon wafers. Despite, the absence of a direct\ncharge transfer between the detector and the double dot structure, an efficient\ndetection is obtained. In particular, unusually large Coulomb peak shifts in\ngate voltage are observed. Results are explained in terms of charge\nrearrangement and the presence of inelastic cotunneling via states at the\nperiphery of the single electron transistor dot.\n