Dwell time characterization of DNA translocation through ITO-SiNx nanopores

Nanopores that integrate indium-tin-oxide (ITO) electrical gates have previously demonstrated the capability of modulating the DNA folding/knotting configurations in their translocation dwell times in such devices. Four ITO-SiNx nanopore devices are fabricated with their sizes in the 8 ∼ 20 nm range. The current blockage and dwell time characterizations using these nanopores are presented for DNAs entering from both the SiNx and ITO sides of the nanopores with 0 V bias applied at the ITO gate. While the current blockage data show little dependence on nanopore sizes, dwell time appears to be shorter with smaller nanopore sizes. Interestingly, the dwell times of DNAs entering from the ITO side are observed to be shorter than those of the reverse direction, suggesting the DNA translocation process is affected by the asymmetry of the layered nanopore structures. This work proves ITO as a compatible material for DNA translocation and provides a basic research for the velocity studies of DNA translocation in gated nanopores.