Ultra flat gold surfaces for use in chemical force microscopy: Scanning probe microscopy studies of the effect of preparation regime on surface morphology

The preparation of ultra flat gold surfaces for use in chemical force micro scopy (CFM) has been studied. The surfaces were studied in terms of substra te effects by comparing mica, Si (110) wafer and glass slides. The effect o f different annealing regimes was also investigated. Measurements on these surfaces were made by both atomic force microscopy (AFM) (in contact and ta pping mode) and by scanning tunneling microscopy (STM). The films contain d ifferent morphologies with respect to grain size and topography. Calculatio ns of surface roughness present values less than 2.5 nm for all surfaces st udied, making the choice of the "flattest" surface difficult if based on cr iteria of surface roughness alone. Additionally, it is shown that different acquisition parameters can produce dissimilar images that have stability a nd reproducibility.