Detection of DNA nucleotides via silicon nanowire field-effect transistor sensors with a nanogap: Semi-empirical modeling

Silicon Nanowire field-effect transistors (SiNW FETs) have become very popular as they enable enhanced sensing capabilities, such as high-sensitivity, selectivity, and real-time detection. This research aimed at studying Silicon Nanowire Field effect transistor with a nanogap that is capable enough to create unique electronic signatures representing individual DNA nucleotides (Adenosine, Guanosine, Thymidine & Cytidine). In this work, two different transistor systems- back-gated SiNW FET and Gate All Around SiNW FET - were studied for the purpose of DNA nucleotide detection. Electronic transport properties such as current, transmission spectrum, and density of states were studied for both types of transistors. In the presence of Adenosine, the Gate All Around sensor reading was significantly enhanced from 0.07 nanoamperes to 3 nanoamperes, greatly improving the sensor's ability to differentiate between nucleotides.The study's findings indicate that the GAA SiNW FET outperforms the back-gated SiNW FET in terms of sensitivity when detecting DNA nucleotides. To examine the mechanics behind this process, non-equilibrium Green's function integrated with a semi-empirical model was utilized. The results showed that each type of DNA nucleotide could be detected by the designed SiNW FET sensor.