High sensitivity biosensors based on germanium nanowires fabricated by Ge condensation technique

• Biosensors based on germanium nanowires were fabricated and applied in biochemical detection.
• The nanostructure of obtained GeNW was stable and had excellent oxidation resistance for storage.
• Surface SiO2 on GeNWs acted as good modification platform for biochemical detection.
• The detection limit was calculated to be 5 fM.

We demonstrate a novel technique to fabricate germanium nanowires (GeNWs) for field effect transistor biosensors. Arrays of core-shell structure GeNWs were “top-down” fabricated by combining the complementary metal-oxide semiconductor (CMOS) compatible technology and Ge condensation technology. The obtained GeNWs had stable SiO2 cladding, which acted as good modification platform for biochemical detection, since SiO2 modification was a mature technology. After the GeNWs were covalently bonded with DNA probe, the nanosensor demonstrated highly sensitive concentration-dependent current change in response to target DNA. This study may pave the way for further application such as the integration of bioelectronics and biosensors with the attractive semiconductor material Ge in future work.