Water adsorbate mediated accumulation gas sensing at hydrogenated diamond surfaces

Hydrogenated diamond (HD) specimens feature a peculiar form of gas response which occurs at room temperature and which is mediated by a thin layer of water that tends to accumulate on HD surfaces as these are exposed to normal atmospheric conditions. HD specimens are known to be sensitive to gases and vapours that are capable of forming acid-base reactions in liquid water. In this paper we show that HD sensors feature a novel kind of accumulating gas response which - under favourable conditions - comes close to an integrator-like behaviour. In this integrator-limit of operation, the HD gas response becomes proportional to the total flow of reactive gases that had been interacting with the water adsorbate layer on top of the HD sensors. (c) 2013 Elsevier B.V. All rights reserved.