First principles study of adsorbed and substitutionally doped Fe atoms in zigzag graphene nanoribbons

We present a systematic investigation to compare the adsorption and substitutional doping of Fe atoms in ZGNR. The present calculations revealed that adsorption and substitutional doping are two different phenomenon which differ in stability. We predict that Fe adsorption in ZGNR is energetically more favourable than substitutional doping. Edge is found to be energetically preferred site for adsorption as well as for substitutional doping. The calculated binding energy (BE) indicates a stronger binding for substitutional doping rather than the adsorption. The optimized C-Fe bond length for substitutional doping is smaller as compared to that for Fe adsorption which support the BE analysis.