Study of Molecular Junctions Metal—DNA—Metal for the DNA Sequencing

The process of the DNA sequencing in solid-state nanopores is considered. The theoretical modeling of ionic, thermionic, and tunnel currents for nanopores with the gold electrodes located in bio-liquids has been carried out. It is shown that both the ionic and thermionic currents are several orders of magnitude weaker than the direct tunneling current, which reaches several hundred of nA. The differences between the values of direct tunnel currents for four DNA nucleotides, as well as for guanine-cytosine and thymine-adenine nucleotide pairs are significant, which makes it easy to identify each DNA nucleotide. The behavior of the differential quantum conductance of the corresponding molecular junctions is also analyzed. The histograms for tunnel currents and conductance for four the DNA and guanine-cytosine and thymine-adenine nucleotides are plotted.