The Merits of a Folded Graphene Nanodevice for Reliable DNA Sequencing

Inspired by controlled folding of graphene experiments, in this study, we demonstrate a folded graphene nanogap device for DNA sequencing. With the aid of first-principles density functional theory (DFT) and nonequilibrium Green's function (NEGF) based methods, we have modeled a solid-state nanodevice comprising a folded graphene nanogap and assessed its potential for detection of four different DNA nucleotides (dAMP, dGMP, dTMP, dCMP). The electronic structure of such a working device is analyzed from the perspective of zero-bias transmission functions and the density of states for all four nucleotides. In order to characteristically distinguish the DNA nucleotides, the corresponding current–voltage (I–V) profiles have been computed, which show noteworthy distinguishable features. From our interesting findings, we have zeroed in on two voltage regimes, namely, 0.2 and 1.1 V, wherein all four DNA nucleotides manifest distinguishable current traces and make their identification plausible with better sensitivity compared to a pure graphene-based nanogap device. We have further analyzed the bias-dependent transmission function to gain a deeper understanding of the molecular and electronic states responsible for distinguishable trends in the current profiles. Our conceptualized folded graphene based nanodevice stands superior to a typical graphene nanoelectrode based device that suffers from reactivity and stability issues. Based on all these important findings, we propose a folded graphene nanogap device to be a reliable, rapid, and robust setup for fast DNA sequencing.