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AFM for Graphene and 2D Materials

Graphene flakes imaged on boron nitride using atomic force microscopy

The 2004 report by Novoselov and Geim on transistors made from single-layer graphitic films created overnight the field of graphene research. This single, free-standing plane of carbon atoms has proven to exhibit many unique and desirable properties: it provides a high surface area, excellent electrical and thermal conductivity, and superior mechanical strength. Graphene is an ideal two-sided surface without a bulk in between, has the highest known room-temperature carrier mobility, 25 times the thermal conductivity of silicon, a reported Young's modulus of ~1 TPa and breaking strength approaching the theoretical limit. Potentials for breakthrough technologies thus abound, including: next generation electronics (quantum computing, spintronics); energy collection and storage (photovoltaics, fuel cells, supercapacitors); nanoelectromechanical (NEMS) devices and resonators; and electrochemical sensors and lab-on-chip biosensors. This has also spurred attendant interest in other 2D materials such as MoS2 and boron nitride films.
 
Atomic force microscopy is a critical enabling technology in graphene research. Its high (sub-angstrom) resolution distinguishes with ease single atomic layers on a substrate, and is suitable for characterizing film quality, such as morphology, roughness, and uniformity. Moreover, AFM imaging requires a probe to be in physical contact with the surface, which makes it possible to determine electrical and mechanical properties simultaneously with topography. Material properties such as conductivity and permittivity, stiffness and dissipation, viscoelastic and friction responses can thus be mapped-out with nanoscale lateral precision. Long-range electrical properties such as electrostatic charge, surface potential, and magnetic fields can be probed as well by bringing the tip in close proximity of the surface during measurement.

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Metrology

  • Film thickness
  • Roughness, morphology, uniformity

Electrical Properties

  • Conductivity and permittivity (sMIM, CAFM)
  • Surface potential (KPFM)
  • Stored charge (EFM)
  • I-V profiles (CAFM)

Magnetic Properties

  • Magnetic force gradients (MFM)

Mechanical Properties

  • Stiffness, Young's modulus (Force Curves, Fast Force Mapping, AM-FM)
  • Elastic modulus, loss modulus, loss tangent (AM-FM, Contact Resonance, Loss Tangent Imaging)
  • Energy dissipation (AM-FM, Contact Resonance, Loss Tangent Imaging)

Tribological Properties

  • Friction (LFM)
  • Adhesion (Force Curves, Fast Force Mapping)

Thermal Properties

  • Thermal conductivity (SThM)
  • Quantum computing, spintronics
  • Electronic circuit components: transistors, field emitters, interconnects, supercapacitors
  • Resistive non-volatile memory technology
  • Transparent electrodes for optoelectronics, photovoltaics, and display technology
  • Energy collection and storage: solar cells, fuel cells, batteries
  • Terahertz plasmon oscillators
  • Sensor technologies: single-molecule sensors, electrochemical sensors, biosensors, lab-on-chip devices
  • Semipermeable membranes for (bio)molecular and ion transport
  • Nanoelectromechanical systems and mechanical resonators

S. Bertolazzi, J. Brivio, and A. Kis, "Stretching and Breaking of Ultrathin MoS2," ACS Nano 5, 9703-9709 (2011). doi:10.1021/nn203879f

S. Bertolazzi, J. Brivio, A. Radenovic, A. Kis, H. Wilson, L. Prisbrey, E. Minot, A. Tselev, M. Philips, M. Viani, D. Walters, and R. Proksch, "Exploring flatland: AFM of mechanical and electrical properties of graphene, MoS2 and other low-dimensional materials," Microscopy and Analysis 27, 21-24 (2013). link to magazine

J. Brivio, D. T. L. Alexander, and A. Kis, "Ripples and Layers in Ultrathin MoS2 Membranes," Nano Lett. 11, 5148-5153 (2011). doi:10.1021/nl2022288

L. Collins, J. I. Kilpatrick, I. V. Vlassiouk, A. Tselev, S. A. L. Weber, S. Jesse, S. V. Kalinin, and B. J. Rodriguez, "Dual harmonic Kelvin probe force microscopy at the graphene-liquid interface," Appl. Phys. Lett. 104, 133103 (2014). doi:10.1063/1.4870074

J. R. Felts, A. J. Oyer, S. C. Hernández, K. E. W. Jr, J. T. Robinson, S. G. Walton, and P. E. Sheehan, "Direct mechanochemical cleavage of functional groups from graphene," Nat. Commun. 6, 6467 (2015). doi:10.1038/ncomms7467

R. Jalili, S. H. Aboutalebi, D. Esrafilzadeh, R. L. Shepherd, J. Chen, S. Aminorroaya-Yamini, K. Konstantinov, A. I. Minett, J. M. Razal, and G. G. Wallace, "Scalable One-Step Wet-Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles," Adv. Funct. Mater. 23, 5345-5354 (2013). doi:10.1002/adfm.201300765

K. Kim, Z. Lee, B. D. Malone, K. T. Chan, B. Alemán, W. Regan, W. Gannett, M. F. Crommie, M. L. Cohen, and A. Zettl, "Multiply folded graphene," Phys. Rev. B 83, 245433 (2011). doi:10.1103/physrevb.83.245433

I. Levchenko, O. Volotskova, A. Shashurin, Y. Raitses, K. Ostrikov, and M. Keidar, "The large-scale production of graphene flakes using magnetically-enhanced arc discharge between carbon electrodes," Carbon 48, 4570-4574 (2010). doi:10.1016/j.carbon.2010.07.055

L. H. Li, J. Cervenka, K. Watanabe, T. Taniguchi, and Y. Chen, "Strong Oxidation Resistance of Atomically Thin Boron Nitride Nanosheets," ACS Nano 8, 1457-1462 (2014). doi:10.1021/nn500059s

Q. Li, X.-Z. Liu, S.-P. Kim, V. B. Shenoy, P. E. Sheehan, J. T. Robinson, and R. W. Carpick, "Fluorination of Graphene Enhances Friction Due to Increased Corrugation," Nano Lett. 14, 5212-5217 (2014). doi:10.1021/nl502147t

Y. Liu, F. Wang, X. Wang, X. Wang, E. Flahaut, X. Liu, Y. Li, X. Wang, Y. Xu, Y. Shi, and R. Zhang, "Planar carbon nanotube-graphene hybrid films for high-performance broadband photodetectors," Nat. Commun. 6, 8589 (2015). doi:10.1038/ncomms9589

A. J. Marsden, M. Phillips, and N. R. Wilson, "Friction force microscopy: a simple technique for identifying graphene on rough substrates and mapping the orientation of graphene grains on copper," Nanotechnology 24, 255704 (2013). doi:10.1088/0957-4484/24/25/255704

N. R. Pradhan, D. Rhodes, Q. Zhang, S. Talapatra, M. Terrones, P. M. Ajayan, and L. Balicas, "Intrinsic carrier mobility of multi-layered MoS2 field-effect transistors on SiO2," Appl. Phys. Lett. 102, 123105 (2013). doi:10.1063/1.4799172

B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, and A. Kis, "Single-layer MoS2 transistors," Nat. Nanotechnol. 6, 147-150 (2011). doi:10.1038/nnano.2010.279

B. Radisavljevic, M. B. Whitwick, and A. Kis, "Integrated Circuits and Logic Operations Based on Single-Layer MoS2," ACS Nano 5, 9934-9938 (2011). doi:10.1021/nn203715c

S. Scharfenberg, D. Z. Rocklin, C. Chialvo, R. L. Weaver, P. M. Goldbart, and N. Mason, "Probing the mechanical properties of graphene using a corrugated elastic substrate," Appl. Phys. Lett. 98, 091908 (2011). doi:10.1063/1.3553228

A. Tselev, N. V. Lavrik, A. Kolmakov, and S. V. Kalinin, "Scanning Near-Field Microwave Microscopy of VO2and Chemical Vapor Deposition Graphene," Adv. Funct. Mater. 23, 2635-2645 (2013). doi:10.1002/adfm.201203435

A. Tselev, N. V. Lavrik, I. Vlassiouk, D. P. Briggs, M. Rutgers, R. Proksch, and S. V. Kalinin, "Near-field microwave scanning probe imaging of conductivity inhomogeneities in CVD graphene," Nanotechnology 23, 385706 (2012). doi:10.1088/0957-4484/23/38/385706

A. Tselev, V. K. Sangwan, D. Jariwala, T. J. Marks, L. J. Lauhon, M. C. Hersam, and S. V. Kalinin, "Near-field microwave microscopy of high-κ oxides grown on graphene with an organic seeding layer," Appl. Phys. Lett. 103, 243105 (2013). doi:10.1063/1.4847675

S. Unarunotai, J. C. Koepke, C.-L. Tsai, F. Du, C. E. Chialvo, Y. Murata, R. Haasch, I. Petrov, N. Mason, M. Shim, J. Lyding, and J. A. Rogers, "Layer-by-Layer Transfer of Multiple, Large Area Sheets of Graphene Grown in Multilayer Stacks on a Single SiC Wafer," ACS Nano 4, 5591-5598 (2010). doi:10.1021/nn101896a

D. Yu, L. Wei, W. Jiang, H. Wang, B. Sun, Q. Zhang, K. Goh, R. Si, and Y. Chen, "Nitrogen doped holey graphene as an efficient metal-free multifunctional electrochemical catalyst for hydrazine oxidation and oxygen reduction," Nanoscale 5, 3457 (2013). doi:10.1039/c3nr34267k