Surface charge transfer doping of germanium nanowires by MoO3 deposition

Abstract

We report on the surface transfer p-type doping of germanium nanowires (GeNWs) via MoO₃ thin film deposition. The GeNWs studied were prepared by a conventional thermal evaporation approach. Electrical property analysis shows that the conductance, hole mobility and concentration were all prominently enhanced after MoO₃ thin film coating. Such a remarkable surface doping effect can be attributed to the surface charge transfer at the GeNWs/MoO₃ interface, which is verified by in situ XPS analysis of GeNWs as a function of increasing MoO₃ coverage. Further hole mobility and concentration evolution study of MoO₃/GeNWs reveals that the GeNWs embedded in the MoO₃ layer can retain their electrical property after storage in air for 3 months. The generality of the above results suggests that the charge transfer doping via surface deposition has great potential in GeNW-based nanoelectronic devices and may also be applicable to the modulation of other semiconductor nanostructures.