Thin Solid Films 409 (2002) 243–247 0040-6090/02/$ - see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0040-6090 Ž 02 . 00141-4 Reversible resistivity change of thin silver films in the spatial afterglow of a nitrogen discharge D. Diesing *, J. Berndt , D. Douai , J. Winter b, a a a Institut fur Experimentalphysik 2, Gebaude NB 5 Ruhr-Universitat Bochum, D-44780 Bochum, Germany a ¨ ¨ ¨ Lehrstuhl fur Oberflachenwissenschaft (IPkM), Heinrich-Heine-Universitat Dusseldorf, D-40225 Dusseldorf, Germany b ¨ ¨ ¨ ¨ ¨ Received 12 July 2001; received in revised form 18 January 2002; accepted 7 February 2002 Abstract Experiments are reported on the interaction of thin (df20 nm) evaporated silver films with the afterglow of an argon nitrogen microwave discharge. A strong increase in the resistivity of the thin silver film (from 2.2=10 to more than 10 V m) due y8 y3 to the interaction with the spatial afterglow of a nitrogen plasma was observed. The initial low resistivity could be recovered by increasing the sample temperature from room temperature to 420 K or by treatment with an argon plasma. The effect is thus reversible. Sputtering processes could not be observed in the spatial afterglow of nitrogen discharges. The experimental results are assigned to dissolved nitrogen compounds in the thin silver film. A possible mechanism for the reversible increase in film resistivity in the nitrogen afterglow may be strong electron localization at the nitrogen-induced lattice defects.  2002 Elsevier Science B.V. All rights reserved. Keywords: Mesoscopic transport; Conductivity; Resistivity; Silver 1. Introduction The electric properties of thin metal films can be influenced by a large number of effects, such as size w1x, surface w2x, or impurity effects w3x. Size effects may influence the conductivity of metals over several orders of magnitude, when the geometry of the metal (width or thickness) becomes comparable with the Fermi wave- length of the conduction electrons. Recent experiments showed the influence of size effects on the resistivity in nanowires and clusters. An example was given by Herzog et al., who reported on a reversible resistivity change over several orders of magnitude in granular metal wires w4x. They explained their results by a first-order electronic phase transition between weakly and strongly localized states. Surface effects on the resistivity of metal films can be observed in the thickness range 10-d-40–50 nm. In this case, adsorbates and defects on the surface change the reflection of the conduction electrons at the metal *Corresponding author. Tel.: q49-211-81-14266; fax: q49-211- 81-14277. E-mail address: diesing@uni-duesseldorf.de (D. Diesing). surface w5x. A microscopic view of the surface resistivity change due to adsorbates has been given by Persson. He related the resistivity increase Dr to the lifetime of the frustrated translation vibration of the adparticle w6x. These surface resistivity effects cause a resistivity change of the order of several percent w7x. The resistivity increase due to the incorporation of impurities are also a well-known phenomenon w3x.A special case is intercalated non-metal atoms in transition metals, which may induce an electron transfer and thereby cause a negative contribution to the resistivity. An example of this is the system of hydrogen in palladium. In noble metals, the solution of non-metal atoms as gases and their influence on the resistivity of the metal has also been often investigated. The influence of gases on the resistivity in this case is given by the distortion of the periodicity of the crystal lattice, which induces an increase in resistivity. For noble metals, this resistivity increase is in the range of 10–100% w8x For silver, hydrogen, deuterium and oxygen show a solubility w9x. For the silver ynitrogen system, no solu- bility was found for neutral molecular nitrogen species w9x.