Amination of NCD Films for Possible Application in Biosensing

Nanocrystalline diamond (NCD) films may be used in biosensing after modification of their surfaces with active functional groups. Here, surface functionalization of O‐ and H‐NCD films with amine groups was made by 2 plasma‐based processes: a) RF plasma treatment in ammonia, b) the deposition of thin amine‐containing plasma polymer via RF magnetron sputtering of nylon target in Ar/N2 mixture. Amination of the NCD films by plasma treatment in NH3 caused an attachment of 1% of primary amines but destroyed the surface conductivity of H‐NCD films. The 5% concentration of NH2 was detected on the NCD covered with the plasma polymer. Moreover, the surface conductivity of H‐NCD films reached 10−7 S. H‐ and O‐terminated NCD films are functionalized by deposition of amine containing plasma polymer and RF plasma treatment in NH3. The concentrations of NH2 groups about 5 and 1% are obtained on diamond surfaces, respectively. I–V measurements show the destruction of H‐NCD surface conductivity after plasma treatment. After amination via polymer it decreases down to 10−7 S.