We demonstrate the possibility in quantifying the Raman intensities for both specimen and substrate layers in a common stacked experimental configuration and, consequently, propose a general and rapid thickness identification technique for atomic-scale layers on dielectric substrates. Unprecedentedly wide-range Raman data for atomically flat MoS(2) flakes are collected to compare with theoretical models. We reveal that all intensity features can be accurately captured when including optical interference effect. Surprisingly, we find that even freely suspended chalcogenide few-layer flakes have a stronger Raman response than that from the bulk phase. Importantly, despite the oscillating intensity of specimen spectrum versus thickness, the substrate weighted spectral intensity becomes monotonic. Combined with its sensitivity to specimen thickness, we suggest this quantity can be used to rapidly determine the accurate thickness for atomic layers.

Our study with AFM clearly demonstrates that cell stiffness is a reliable quantitative indicator of migration potential, and very likely metastatic potential, even in morphologically similar cells. And increased cell stiffness may be a key nanomechanical feature in inhibition of metastasis.

We present the temperature-dependent carrier mobility of atomically thin MoS2 field-effect transistors on crystalline hexagonal boron nitride (h-BN) and SiO2 substrates. Our results reveal distinct weak temperature dependence of the MoS2 devices on h-BN substrates. The room temperature mobility enhancement and reduced interface trap density of the single and bilayer MoS2 devices on h-BN substrates further indicate that reducing substrate traps is crucial for enhancing the mobility in atomically thin MoS2 devices.

A comprehensive analysis of the electrical current passing through the tip-substrate junction during oxidation of silicon by scanning probe microscopy (SPM) is presented. This analysis of experimental results under dc-bias conditions resolves the role of electronic and ionic contributions, especially for the initial stages of the reaction, determines the effective contact area of the tip-substrate junction, and unifies the roles of space charge and meniscus formation. In Part I of this work, we demonstrate that SPM oxidation is governed by a maximum charge density generated by electronic species within the junction at the onset of the oxidation process. Excess charge is channeled into lateral diffusion, keeping the charge density within the reaction zone constant and reducing the aspect ratio of the resulting oxide features. A uniform charge density implies that SPM oxides contain a fixed defect concentration, in accordance with the space-charge model. The effective (electrical) thickness of SPM oxides determined by these defects is investigated by Fowler-Nordheim analysis. We conclude that most of the electrical current involved in high voltage SPM oxidation of Si does not actually induce surface oxide growth, and that lateral diffusion and small aspect ratios are unavoidable aspects of contact-mode conditions.

Ferromagnetic-film-coated carbon nanotube (CNT) probes were employed in a magnetic force microscope (MFM) observation. We succeeded in making a uniform ferromagnetic film on the CNT probes by improving the coating process and selecting materials. The performance of the CoFe-coated CNT probe was evaluated in ultra-high-density perpendicular magnetic storage media with densities from 600 to 1100 k flux changes per inch (FCI). The magnetic domain structure of the magnetic storage media was clearly observed up to 1100 kFCI. The ultimate lateral resolution of the newly developed MFM probes is down to about 10 nm, which exceeds the bit length of a magnetic recording with a density of Tbit inch −2 .

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Faradaic current during anodic oxidation is measured over a relative humidity range of 40–70% using an atomic force microscope with humidity control. The level of detected current during the fabrication of oxide dots on H-passivated Si(001) is in the picoampere (pA) level. Current flow began immediately (within a few milliseconds) after applying an oxidation voltage above a threshold value and decreased with time according to oxide growth. The total charge resulting from the current flow was calculated by integrating the current–time curve and was found to agree well with an estimation of expected current from the volume of the fabricated oxide dots. Actual monitoring of the oxidation process by the Faradaic current is demonstrated during the fabrication of a two-dimensional lattice.

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