Influence of Surface State on Biochemical Sensing Using SiGe Nanowire

Nanowires are extensively used to fabricate highly sensitive electrical sensors for detection of biological and chemical species. The hole mobility can be promoted by the increasing Ge fraction in SiGe, achieved by the oxidation-induced Ge condensation. However, oxidation increases the number of surface states, which brings the nonnegligible contribution in mobility degradation. In this work, 3-aminopropyltrimethoxysilane (APTMS) was used as a biochemical reagent to modify the surface of SiGe nanowires, then bonding to bio-linker, bis (3-sulfo-N-hydroxysuccinimide ester) sodium salt (BS3). Various methods have been proposed for increasing sensitivity of boron-doped SiGe nanowires, such as capping layer, surface treatment, and annealing temperature.