Polysilicon Nanowire Sensor Devices Based on High-k Dielectric Membrane for pH Sensing and DNA Detection

The pH sensing characteristics of poly-Si nanowires with high-k sensing membranes are investigated. As a result, the sensing membrane of HfO2 exhibits higher sensitivity and better reproducibility test as compared with TEOS SiO2, Al2O3, TiO2 films. The sensor device with HfO2 dielectric membrane reveals a great pH sensitivity of 172.8 nA/pH. In additon, the label-free DNA detection ability of the poly-Si nanowires is also demonstrated. The 10-base-long single-strained homopolymers DNA molecule solution with an ultra-low concentration of 0.01nM can be detected by using HfO2 sensing film. Such a poly-Si nanowires structure with HfO2 sensing membrane is very suitable for future biochemical sensors applications.