Measurements of current-voltage characteristics of separate single GaAs nanowhiskers

In this work a method is proposed for measurements of current-voltage (I-V) characteristics for individual semiconductor nanowhiskers (NWs) standing on the growth surface. It is shown that conductive probe of atomic force microscope (AFM) can be placed at the top of nanowhiskers with a great precision and used as a stable local electrode. For that, a fixation of NWs is necessary to avoid lateral bending of NWs under pressure of AFM probe. In the present work we have studied current-voltage characteristics of NWs with radial heterostructure GaAs/AlGaAs grown under Au droplets on GaAs substrate. For fixation, NWs were partially overgrown with GaAs layer. The current-voltage characteristics measurements on the fixed NWs permitted to investigate the Si-doping of GaAlAs/GaAs NWs. They were found to be Schottky barrier p-type curves, what shows that Si-atoms incorporate into GaAs NWs with a formation of acceptor centres contrary to the case of bulk GaAs. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)