n-Type Doping of Vapor–Liquid–Solid Grown GaAs Nanowires
Solid State Electronics Department and CeNIDE, University of Duisburg-Essen, Lotharstr. 55, 47048, Duisburg, Germany
Nanoscale Res Lett 2011, 6:65 doi:10.1007/s11671-010-9815-7Published: 7 October 2010
In this letter, n-type doping of GaAs nanowires grown by metal–organic vapor phase epitaxy in the vapor–liquid–solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations ND of GaAs nanowires are found to vary from 7 × 1017 cm-3 to 2 × 1018 cm-3. The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal–insulator-semiconductor field-effect transistor devices.