Structure and nanotribology of thermally deposited gold nanoparticles on graphite

Abstract

a b s t r a c tWe present experiments involving the structural and frictional characterization of gold nanoparticles (AuNP) thermally deposited on highly oriented pyrolytic graphite (HOPG). The effect of thermal deposition amount, as well as post-deposition annealing on the morphology and distribution of gold on HOPG is studied via scanning electron microscopy (SEM) measurements, while transmission electron microscopy (TEM) is utilized to confirm the crystalline character of the nanoparticles. Lateral force measurements conducted via atomic force microscopy (AFM) under ambient conditions are employed to investigate the nanotribological properties of the gold nanoparticles as a function of normal load. Finally, the increase in lateral force experienced at the edges of the nanoparticles is studied as a function of normal load, as well as nanoparticle height. As a whole, our results constitute a comprehensive structural and frictional characterization of the AuNP/HOPG material system, forming the basis for nanotribology experiments involving the lateral manipulation of thermally deposited AuNPs on HOPG via AFM under ambient conditions.

Chemical effects on the sliding friction of Ag and Au(111)

“…More recently, Cihan et al pointed at the importance of chemical inertness of the tribological couple and the abesence of contamination at the sliding interface for superlubricity. In ambient conditions, the authors reported a 2/ 3 n F -dependence of the friction force on gold [8]. However, the friction force arising from sliding a gold nano-island deposited on graphite yielded similar friction force values as in UHV conditions [9].…”

“…The growth of thin metallic films onto silicon devices for operation in reciproc motion appears to be a feasible alternative. Recently, the nanoscale friction and wear behavior of metals has been investigated [5][6][7][8][9][10]. In the low load regime where adhesive force prevails, friction has been reported to vanish and the sliding of a slingle asperity onto single crystalline metallic surfaces was characterized by atomic stick-slip [5].…”

“…Further, the authors demonstrated the role of passivating selfassembled monolayer in suppressing the formation of such a neck and the switching of nanoscale friction on Au(111) by electrochemical control. Moreover, the nanotribology of thermanlly deposited gold on graphite was studied [8,9]. In contrast to single-asperity friction measurements performed in ultra-high vacuum (UHV)-conditions in Refs.…”

“…In contrast to single-asperity friction measurements performed in ultra-high vacuum (UHV)-conditions in Refs. [5,6], the authors reported on 2 / 3 n F -dependence of the friction force on gold nanoparticles measured in ambient conditions, where F n is the normal force [8]. In Ref.…”

Experimental Studies of Nanometer-Scaled Single-Asperity Contacts with Metal Surfaces

“…[6,7], friction between Au islands and graphite was studied. AF 2=3 n dependence of the friction force on gold islands measured in ambient conditions was observed, where F n is the normal force [6]. These contrasts with results in Refs.…”