The Ge enhance the sensitivity for bio-sensor

Nanowire is mainly used in biological sensor because it has the high surface-to-volume ratio. In this study, we have successfully fabricated the N-SiGe nanowire with different Ge concentration by side-wall spacer technique respectively. The 3-amino-propyltrime-thoxy-silane (APTS) was used to modify the surface, which can connect the bialinker. The. conductance of SiGe nanowire increases owing to APTS with positive charge. The his (sulfosuccinimidyl) suberate sodium (BS3) as the bialinker connects to APTS, and the conductance decreases because of negative charge. Finally, the protein immunoglobulin G (IGG) is linked to BS3, and the conductance reduces for negative charge. Comparing the conductance change; the SiGe nanowire with higher Ge concentration improved the sensitivity. But the over-higher Ge concentration (40%) did not increase the sensitivity; the reason maybe the higher defect appears at the surface as higher Ge concentration.