Robert W. Carpick

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Using friction force microscopy, we compared the nanoscale frictional characteristics of atomically thin sheets of graphene, molybdenum disulfide (MoS2), niobium diselenide, and hexagonal boron nitride exfoliated onto a weakly adherent substrate (silicon oxide) to those of their bulk counterparts. Measurements down to single atomic sheets revealed that(More)
The atomic force microscope can provide information on the atomic-level frictional properties of surfaces, but reproducible quantitative measurements are difficult to obtain. Parameters that are either unknown or difficult to precisely measure include the normal and lateral cantilever force constants (particularly with microfabricated cantilevers), the tip(More)
This letter reports the implementation of ultrathin (100 nm) aluminum nitride (AlN) piezoelectric layers for the fabrication of vertically deflecting nanoactuators. The films exhibit an average piezoelectric coefficient (d31~−1.9 pC/N), which is comparable to its microscale counterpart. This allows vertical deflections as large as 40 nm from 18 μm long and(More)
We have studied the variation of frictional force with externally applied load for a Pt-coated atomic force microscope tip in contact with the surface of mica cleaved in ultrahigh vacuum. At low loads, the frictional force varies with load in almost exact proportion to the area of contact as predicted by the Johnson-KendallRoberts ( JKR) theory [K. L.(More)
A. V. Sumant,1,* D. S. Grierson,1 J. E. Gerbi,2,† J. A. Carlisle,2,3,‡ O. Auciello,2,3 and R. W. Carpick1,§ 1Department of Engineering Physics, University of Wisconsin–Madison, Wisconsin 53706, USA 2Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA 3Center for Nanoscale Materials, Argonne National Laboratory, Argonne,(More)
The impressively low friction and wear of diamond in humid environments is debated to originate from either the stability of the passivated diamond surface or sliding-induced graphitization/rehybridization of carbon. We find ultralow friction and wear for ultrananocrystalline diamond surfaces even in dry environments, and observe negligible rehybridization(More)
Using friction force microscopy, we have investigated the frictional behavior of graphene deposited on various substrates as well as over micro-fabricated wells. Both graphene on SiO2/ Si substrates and graphene freely suspended over the wells showed a trend of increasing frictionwith decreasing number of atomic layers of graphene. However, this trend with(More)
As the size of electronic and mechanical devices shrinks to the nanometre regime, performance begins to be dominated by surface forces. For example, friction, wear and adhesion are known to be central challenges in the design of reliable microand nano-electromechanical systems (MEMS/NEMS). Because of the complexity of the physical and chemical mechanisms(More)
Atomic force microscopy (AFM) is a powerful tool for studying tribology (adhesion, friction, and lubrication) at the nanoscale and is emerging as a critical tool for nanomanufacturing. However, nanoscale wear is a key limitation of conventional AFM probes that are made of silicon and silicon nitride (SiNx). Here we present a method for systematically(More)
We use atomic force microscopy (AFM) to determine the frictional properties of nanoscale single-asperity contacts involving octadecyltrichlorosilane (OTS) monolayers and silicon. Quantitative AFM measurements in the wearless regime are performed using both uncoated and OTS-coated silicon AFM tips in contact with both uncoated and OTS-coated silicon(More)