US team gives graphene a tuneable bandgap

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An interdisciplinary team of scientists at the US Naval Research Laboratory (NRL) says it has shown that hyperthermal ion implantation (HyTII) can be an effective means of doping graphene with nitrogen atoms. The process is said to result in a low defect film with a tuneable bandstructure.

graphene was isolated from bulk graphite, a plethora of remarkable electronic and spintronic properties has emerged. “However, few applications are forthcoming because graphene lacks a bandgap and its doping is difficult to control, rendering graphene devices competitive only for highly specialised device technologies.”

Addressing this issue, NRL scientists developed an HyTII system with the precision and control needed to implant nitrogen (N+) into graphene, thereby achieving doping via direct substitution.

Dr Cress said: “In our study, we determined the range of hyperthermal ion energies that yielded the highest fraction of nitrogen doping, while minimising defects, and we were successful in confirming the inherent depth control of the HyTII process.”

“Our measurements strongly indicate that we have fabricated a graphene film with a tuneable bandgap, low defect density and high stability,” said NRL research physicist Dr Adam Friedman. “We therefore hypothesise that HyTII graphene films have great potential for electronic or spintronic applications for high quality graphene where a transport or bandgap and high carrier concentration are desired.”