  In the last decade, solid state nanopores nanogaps have attracted significant
interest in the rapid detection of DNA nucleotides. However, reducing the noise
through the controlled translocating of the DNA nucleobases is a central issue
for the developing nanogap nanopore based DNA sequencing to achieve single
nucleobase resolution. Furthermore, the high reactivity of the graphene pores
gaps exhibits clogging of the pore gap, leading to the blockage of the pores
gaps, yielding sticking, and irreversible pore closure. To address the
prospective of functionalization of carbon nanostructure and for accomplishing
this objective, herein, we have studied the performance of functionalized
closed end cap carbon nanotube CNT nanogap embedded electrodes which can
improve the coupling through nonbonding electrons and may provide the
possibility of N and O and H pi interaction with nucleotides, as single
stranded DNA is transmigrated across. We have investigated the effect of
functionalizing the closed end cap CNT6,6 electrodes with purine adenine,
guanine and pyrimidine thymine, cytosine molecules. Weak hydrogen bonds formed
between the probe molecule and target DNA nucleobase enhance the electronic
coupling and temporarily stabilize the translocating nucleobase against the
orientational fluctuations, which may reduce noise in the current signal during
experimental measurements. The findings of our density functional theory and
non equilibrium Greens function based study indicates that this modeled setup
could allow DNA nucleotide sequencing with a better and reliable yield, giving
current traces that differ by at least 1 order of current magnitude for all
four target nucleotides. Thus, we feel that functionalized CNT nanogap embedded
electrodes may be utilized for controlled DNA sequencing.
