The thought of utilizing graphene in digital electronics lacks the presence of an inherent band gap. But over few years, there have been multiple approaches, which have been successful in fixing up a band gap into this material. One of the most reliable methods was the nitrogen doping, which in reality boosts the conductivity of the material rather than reducing it.
Now the U.S. Naval Research Laboratory (NRL)’s researchers have introduced a novel technique for graphene’s nitrogen doping that can regulate precisely where the dopants are located in the graphene lattice. Such accurate placement of the dopants diminishes defects and offers enhanced material stability.
“Integration of nitrogen into the lattice of graphene has been successful with other methods including during the post-growth and growth annealing processes,” says Cory Cress, a scientist with NRL. “But the method we have used is not the same in the way we can regulate the placement of the dopants, both in their depth and spatially (if utilizing proliferate layer graphene sample). Typically, the replacement of an impurity, for instance, nitrogen, without extra defects is suitable for transforming the band structure as it maintains the essential carriage properties of graphene.”
The special characteristics of nitrogen as a dopant for graphene are based on the truth that it has one number of electrons than carbon. When nitrogen is situated into the lattice of graphene, its entire links are satisfied, and the additional electron is freely movable throughout the layer of graphene. This augments the concentration of electrons in the material, which is also termed as n-type doping and enhances the conductivity.
Traditional researchers have identified that highlights defects created in graphene i.e. removal of one carbon atom cannot alter the intrinsic level of doping, according to Cress. “In simple terms, flaws in graphene are neutrally charged so that they cannot be employed to controllably develop a band-gap, although flaws diminish the carriage due to enhanced scattering off defects,” he states.
While other dopants were not able to achieve the same level, nitrogen is the perfect n-type dopant for graphene when it is integrated utilizing the hyperthermal ion implantation procedure that the NRL researchers have used. It is because nitrogen possesses similar size and mass equivalent as carbon, making the possibility of substitution high.
In their analysis, the NRL researchers identified a huge negative magneto resistance that scaled with the absorption of nitrogen implantation and a band structure alteration, which can be accurately tunable with the nitrogen content. It is because, in the lattice, the things are fixed.
Adam L. Friedman, the physicist research states, “Our experimentations of such devices robustly indicate that we have eventually fashioned a graphene film with an adjustable bandgap, high stability, and low defect density. Hence, we hypothesize that HyTII graphene layers have a high potential for spintronic or electronic applications for high-quality graphene where are bandgap or transport, and big carrier concentration are desired.”
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