Local, direct-write, damage-free thinning of germanium nanowires

Abstract

A crystallinity-retaining, implantation-free focused electron beam induced etching (FEBIE) process has been exploited to modify germanium nanowires. This technique shows a high selectivity to the metal contacts applied to the nanowires as well as to the substrate which did not exhibit significant etching. Raman-spectroscopic as well as electrical measurements have been performed on the FEBIE-modified nanowires. Experimental data obtained in this study suggest than unintentional stress is often applied to the nanowires by the defined electrical contacts. Electrical measurements indicate that the electronic properties of the as-grown Ge nanowires can be significantly altered already by a slight surface modification, resulting in an increased conductivity of more than two orders of magnitude.