RF plasma functionalized carbon surfaces for supporting sensor architectures

Carbon has a number of properties that make it ideal for use in sensor and electrical applications. Using radio frequency plasma with different precursor gases and operating plasma conditions, it is possible to pre-treat a variety of carbon surfaces in preparation for further molecular attachment, or surface functionalization. Research in our laboratory involves studies on highly ordered pyrolytic graphite (HOPG) as a model carbon substrate and pyrolysed photoresist films (PPF). Plasma treated surfaces have been characterised using a variety of surface sensitive techniques. We will report on results obtained using X-ray photoelectron spectroscopy to probe the chemical nature of the treated surfaces, and hence the extent of treatment. Time of flight secondary-ion mass spectrometry (ToFSIMS) has been utilised to determine the extent of hydrogenation after plasma treatment. Scanning tunnelling microscopy (STM) measurements provide morphological information about the treated surfaces, in particular damage and a severe change in surface structures that may be caused by various plasma treatments. Etching and/or nucleation and growth features are also observed and will be discussed, with the types of features and their distribution strongly dependent on the precursor gas that is used to support the plasma.