Adsorption of ammonia on graphene

Hugo E. Romero, Prasoon Joshi, Awnish K. Gupta, Humberto R. Gutierrez, Milton W. Cole, Srinivas A. Tadigadapa, Peter C. Eklund

Research output: Contribution to journalArticlepeer-review

183 Scopus citations


We report on experimental studies of NH3 adsorption/desorption on graphene surfaces. The study employs bottom-gated graphene field effect transistors supported on Si/SiO2 substrates. Detection of NH 3 occurs through the shift of the source-drain resistance maximum ('Dirac peak') with the gate voltage. The observed shift of the Dirac peak toward negative gate voltages in response to NH3 exposure is consistent with a small charge transfer (f∼0.068 0.004 electrons per molecule at pristine sites) from NH3 to graphene. The desorption kinetics involves a very rapid loss of NH3 from the top surface and a much slower removal from the bottom surface at the interface with the SiO 2 that we identify with a Fickian diffusion process.

Original languageEnglish (US)
Article number245501
Issue number24
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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