ON THE AIR INFLUENCE ON THE SURFACE-AREA OF CLEAN ANNEALED GOLD FILM AND PYREX GLASS

The influence of air on the surface area of thin gold films deposited onto Pyrex glass under ultra-high vacuum (UHV) conditions and on Pyrex glass has been investigated. The samples' surface area was determined ill situ by the BET (Brunauer-Emmett-Teller) adsorption isotherm meth od and ex situ by Atomic Force Microscopy (AFM) in air. The surface ar ea of clean, annealed, continuous and non-continuous gold film, measur ed in situ under UHV conditions by the BET adsorption method, is sever al times greater than its geometric area, whereas calculated from thei r air AFM images is equal to their geometric area. The surface area of clean, annealed gold film, prepared under UHV conditions but then exp osed to air and again determined by the BET isotherm method is several times smaller than that not exposed to air. The Pyrex glass surface a rea, calculated from its air AFM image and measured by the BET isother m method is equal to its geometric area.