Individual charge traps in silicon nanowires
Measurements of location, spin and occupation number by Coulomb blockade spectroscopy
CEA DRFMC, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
2 CEA LETI, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
Published online: 22 December 2006
We study anomalies in the Coulomb blockade spectrum of a quantum dot formed in a silicon nanowire. These anomalies are attributed to electrostatic interaction with charge traps in the device. A simple model reproduces these anomalies accurately and we show how the capacitance matrices of the traps can be obtained from the shape of the anomalies. From these capacitance matrices we deduce that the traps are located near or inside the wire. Based on the occurrence of the anomalies in wires with different doping levels we infer that most of the traps are arsenic dopant states. In some cases the anomalies are accompanied by a random telegraph signal which allows time resolved monitoring of the occupation of the trap. The spin of the trap states is determined via the Zeeman shift.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 73.20.Hb – Impurity and defect levels; energy states of adsorbed species / 75.75.+a – Magnetic properties of nanostructures
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007