n-Type Doping of Vapor–Liquid–Solid Grown GaAs Nanowires

Abstract

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.

Spatially resolved photoelectric performance of axial GaAs nanowire pn-diodes

“…A mean hole concentration of 2 × 10 19 cm -3 was realized with zinc for p-doping, while n-doping with a mean electron concentration of 1 × 10 18 cm -3 was obtained using tin. The carrier concentrations in the nanowires were determined by a mobility vs. carrier concentration model discussed elsewhere [21,22].…”

Zn-doping of GaAs nanowires grown by Aerotaxy

“…In 1992, Haraguchi et al first demonstrated GaAs pn junctions in nanowires using MOVPE [15]. Since then, only a few reports on in situ doping of GaAs nanowires have been published [16][17][18], and many fundamental questions concerning the doping mechanism still remain. For example, it is not well known how dopant atoms incorporate into the nanowires during the growth: via the metal particle [16] or by diffusion from the side facets [19].…”

Doping incorporation paths in catalyst-free Be-doped GaAs nanowires

“…By comparing the two samples we can separate the transport contribution due to the VLS step and obtain the contribution to the conductivity from the VS step. The doping contribution from the VLS step is negligible indicating that the flux of Be atoms to liquid-solid growth front is relatively small 25,26 . We therefore deduce that the incorporation path of Be through the droplet can be neglected.…”