Surface electrical properties of stainless steel fibres: An AFM-based study

tAtomic force microscopy (AFM) electrical modes were used to study the surface electrical propertiesof stainless steel fibres. The surface electrical conductivity was studied by current sensing AFM and I–Vspectroscopy. Kelvin probe force microscopy was used to measure the surface contact potential. The oxidefilm, known as passivation layer, covering the fibre surface gives rise to the observation of an apparentlysemiconducting behaviour. The passivation layer generally exhibits a p-type semiconducting behaviour,which is attributed to the predominant formation of chromium oxide on the surface of the stainless steelfibres. At the nanoscale, different behaviours are observed from points to points, which may be attributedto local variations of the chemical composition and/or thickness of the passivation layer. I–V curves arewell fitted with an electron tunnelling model, indicating that electron tunnelling may be the predominantmechanism for electron transport.