We have measured the electrical response to NO2, N2, NH3 and CO for epitaxial graphene and quasi freestanding epitaxial graphene on 6H-SiC substrates. Quasi freestanding epitaxial graphene shows a 6 fold increase in NO2 sensitivity compared to epitaxial graphene. Both samples show a sensitivity better than the experimentally limited 1 ppb. The strong increase in sensitivity of quasi freestanding epitaxial graphene can be explained by a Fermi-energy close to the Dirac Point leading to a strongly surface doping dependent sample resistance. Both sensors show a negligible sensitivity to N2, NH3 and CO.
@article{arxiv.1305.4737,
title = {High sensitive quasi freestanding epitaxial graphene gassensor on 6H-SiC},
author = {I. Iezhokin and P. Offermans and S. H. Brongersma and A. J. M. Giesbers and C. F. J. Flipse},
journal= {arXiv preprint arXiv:1305.4737},
year = {2015}
}