Integrating 1D and 2D nanostructures with clean silicon and III-V semiconductor surfaces represents an interesting route towards future hybrid electronic systems. In this effort, we are exploring the integration of carbon nanotubes, graphene and graphene nanoribbons (GNRs) with clean semiconductor surfaces. A key challenge is the fabrication of ‘clean’ nanostructure-substrate systems. We have addressed this by developing a simple dry contact transfer (DCT) process that enables the deposition of nanostructures onto atomically clean surfaces in ultrahigh vacuum. STM imaging and spectroscopy, coupled with our atomic resolution STM-based hydrogen resist process have been used to study the interactions of carbon nanotubes, graphene and atomically precise graphene nanoribbons with silicon, GaAs and InAs substrates. In these experiments, we have observed the metallic zigzag edge state in graphene¹, carbon nanotube-substrate lattice alignment effects², and the electronic structure of GNRs³. This talk will also show a method for creating sub-5nm metal wires for contacting nanostructures⁴, a SPM probe sharpening technique for producing 1 nm radii probes⁵, and a technique for improving the electronic performance of carbon nanotube array transistors as well as the structural and thermal performance of CNT-based composite materials⁶.

References:

1. Ritter, K.; Lyding, J., The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbons. Nature Materials 2009,8 (3), 235-242.

2. Ruppalt, L.; Lyding, J., Charge transfer between semiconducting carbon nanotubes and their doped GaAs(110) and InAs(110) substrates detected by scanning tunnelling spectroscopy. Nanotechnology 2007,18 (21).

3. Radocea, A.; Sun, T.; Vo, T.; Sinitskii, A.; Aluru, N.; Lyding, J., Solution-Synthesized Chevron Graphene Nanoribbons Exfoliated onto H:Si(100). Nano Letters 2017,17 (1), 170-178.

4. Ye, W.; Martin, P. A. P.; Kumar, N.; Daly, S. R.; Rockett, A. A.; Abelson, J. R.; Girolami, G. S.; Lyding, J. W., Direct Writing of Sub-5 nm Hafnium Diboride Metallic Nanostructures. Acs Nano 2010,4 (11), 6818-6824.

5. Schmucker, S.; Kumar, N.; Abelson, J.; Daly, S.; Girolami, G.; Bischof, M.; Jaeger, D.; Reidy, R.; Gorman, B.; Alexander, J.; Ballard, J.; Randall, J.; Lyding, J., Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography. Nature Communications 2012,3.

6. Do, J.; Estrada, D.; Xie, X.; Chang, N.; Mallek, J.; Girolami, G.; Rogers, J.; Pop, E.; Lyding, J., Nanosoldering Carbon Nanotube Junctions by Local Chemical Vapor Deposition for Improved Device Performance. Nano Letters 2013,13 (12), 5844-5850.

Oil powers modern economies [1]. Yet only 30% of oil is recovered from a typical reservoir [2]. The reservoirs of Saudi Arabia, which provide over 10% of the world’s oil [3], are unusual . T hey are highly saline, with concentrations of up to 120,000 ppm total dissolved solids (TDS), the temperatures can exceed 100^o C, and the emulsion of oil and brine is dispersed within small fissures in carbonate rock. These conditions are challenging for the unhindered diffusion of the nanoparticle tracers that are used to map an oil field from one well to the next [4]. In this study, bare and carboxyl-terminated atomic-force microscope tips and calcite surfaces acted as surrogates for nanoparticle tracers and carbonate rocks, respectively. They were immersed in three fluids: brine (120K ppm TDS), seawater (60K ppm TDS), and calcium-doped seawater (~60K ppm TDS). Surprisingly, the amount of total dissolved solids was not a good predictor of the tip-sample adhesion. Rather, specific ion effects were important; adding calcium to seawater brought the adhesion down to the ~100 pN levels of brine as compared to the ~400 pN levels of seawater . The adhesion for the carboxyl-terminated tips was greater (reaching into the nN-range) than for the bare tips, but the same trends were observed. These results can be used where fresh water for oil recovery is in short supply. The addition of calcium to seawater should mitigate nanoparticle-rock adhesion and allow more efficient diffusion of nanoparticle tracers through a reservoir, which could in turn lead to better oil recovery and help ensure a stable supply of an essential global resource.

1. Marder, Michael, Tadeusz Patzek, and Scott W. Tinker. "Physics, fracking, fuel, and the future." Physics Today 69.7 (2016): 46-52.

2. Lake, Larry W. "Enhanced oil recovery." (1989): 17-39.

3. Key world energy statistics. International Energy Agency: 2016, https://www.iea.org/

4. Berlin, Jacob M., et al. "Engineered nanoparticles for hydrocarbon detection in oil-field rocks." Energy & Environmental Science 4.2 (2011): 505-509.

5. S.L. Eichmann and N.A. Burnham, “Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids.” submitted.

Muscovite type mica is an inorganic material most commonly used as in various electronic devices. Mica also satisfies many characteristics such as excellent thermal stability, high dielectric strength, larger dielectric constant, high Q factor, and high electrical resistivity needed for organic field effect transistors (OFETs) 1-2. We use the near-field imaging and nano-FTIR techniques to investigate nanoscale absorption properties of mica exfoliated on SiO2 substrate in the frequency range of 4 – 15 μm.

References

1. Castellanos-Gomez, A.; Poot, M.; Amor-Amorós, A.; Steele, G. A.; van der Zant, H. S. J.; Agraït, N.; Rubio-Bollinger, G., Mechanical properties of freely suspended atomically thin dielectric layers of mica. Nano Research 2012, 5 (8), 550-557.

2. Lu, X. F.; Majewski, L. A.; Song, A. M., Electrical characterization of mica as an insulator for organic field-effect transistors. Organic Electronics 2008, 9 (4), 473-480.

Here I introduce our recent progresses in measurement of luminescence and absorption spectra and in plasmon-induced reaction at a single-molecule level using a scanning tunnelling microscope equipped with optical detection/excitation facilities.