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The electronic properties of thin layer transition metal dichalcogenides have raised considerable interest in the fabrication of advanced field-effect transistors and ultrasensitive sensors. Downscaling those devices to the nanoscale depends on the development of cost-effective and robust alternative nanolithographies. Here we demonstrate the direct, resist-less and reproducible nanopatterning of tungsten diselenide thin layers. By using oxidation scanning probe lithography (o-SPL) we have generated arrays of dots with a width of 13 nm and periodicity of 40 nm. We have also patterned a point contact of 35 nm and a nanoscale field-effect transistor. The direct and resistless fabrication of WSe2 nanoscale devices by oxidation scanning probe lithography opens a straightforward and reliable method for processing transition metal dichalcogenides materials. [ABSTRACT FROM AUTHOR]

Thin layer MoS2-based field effect transistors (FET) are emerging candidates to fabricate very fast and sensitive devices. Here, we demonstrate a method to fabricate very narrow transistor channel widths on a single layer MoS2 flake connected to gold electrodes. Oxidation scanning probe lithography is applied to pattern insulating barriers on the flake. The process narrows the electron path to about 200 nm. The output and transfer characteristics of the fabricated FET show a behavior that is consistent with the minimum channel width of the device. The method relies on the direct and local chemical modification of MoS2. The straightforward character and the lack of specific requirements envisage the controlled patterning of sub-100nm electron channels in MoS2 FETs. [ABSTRACT FROM AUTHOR]

Silicon nanowires are key elements to fabricate very sensitive mechanical and electronic devices. We provide a method to fabricate sub-12 nm silicon nanowires in thickness by combining oxidation scanning probe lithography and anisotropic dry etching. Extremely thin oxide masks (0.3-1.1nm) are transferred into nanowires of 2-12 nm in thickness. The width ratio between the mask and the silicon nanowire is close to one which implies that the nanowire width is controlled by the feature size of the nanolithography. This method enables the fabrication of very small single silicon nanowires with cross-sections below 100 nm². Those values are the smallest obtained with a top-down lithography method. [ABSTRACT FROM AUTHOR]

We demonstrate that local oxidation nanolithography can be performed in liquid environments different from aqueous solutions with a significant improvement in the aspect ratio of the fabricated motives. Here, we perform a comparative study of noncontact atomic force microscopy oxidation experiments in water and ethyl alcohol. The growth rate of local oxides can be increased by almost an order of magnitude by using oxyanions from ethyl alcohol molecules. We propose that the enhanced growth rate is a consequence of the reduction of the trapped charges within the growing oxide. The present results open the possibility of using local oxidation nanolithography to directly fabricate vertical oxide structures while keeping lateral sizes in the nanometer range. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Analyzes the atomic-scale manipulation in air with the scanning tunneling microscope. Removal of three atoms from a flat surface in air; Mechanisms for producing the subnanometer marks; Potential for high density storage of information.

Examines the effects of elastic and inelastic interactions on phase contrast images in tapping-mode scanning force microscopy. Simulation of the cantilever-tip ensemble as a harmonic oscillator; Association of phase contrast with elastic modulus variations; Correlation between phase shift and tip-sample equilibrium separation.

Evaluates the operation of the scanning tunneling microscope (STM) in the near field emission regime. Prediction of subatomic resolution in a direction normal to the surface; Calculation of the effective width of a monoatomic step at constant current; Application of the STM mode.

Examines the nanometer-scale modification of semiconductor and metallic samples by field emission scanning microscopy. Methods for the fabrication of nanometer-scale structures and devices; Parameters controlling the tip-membrane distance; Degree of precision and potential of the method for nanometer-scale modification.