A back-gate controlled silicon nanowire sensor with sensitivity improvement for DNA and pH detection

Silicon nanowire field-effect transistors (SiNW-FETs) are emerging as powerful chemical and biological sensors with various attractive features including high sensitivity and direct electrical readout. However, limited systematic studies have appeared on how the working voltage affects their sensitivity. Here we demonstrate that the current change rate of SiNW-FETs can be exponentially enhanced in the subthreshold regime by both analyses of FET's theory model and electrical characteristics. On that basis, the back-gate controlled sensors' detection sensitivity for DNA and pH value appears great improvement when working in the subthreshold regime, which shows that optimization of SiNW-FET operating conditions, can provide significant improvement for the limits of SiNW-FET nanosensors, making it possible for higher-accuracy chemical and biological molecules detection.