Titanium Nanostructures Research Articles

Technology platform for the fabrication of titanium nanostructures

This paper presents two approaches for the fabrication of top-down titanium nanostructures. The first approach involves electron beam lithography followed by a tailored titanium plasma etching. The two main challenges of this process lie in the optimization of the negative tone Ma–N electroresist resolution and in the definition of a controlled titanium etching process for titanium patterns less than 20 nm thick and wide. The second proposed approach is a damascene process where the titanium nanostructures are buried in the oxide. Very shallow and narrow (20 nm × 20 nm) trenches are first patterned in the oxide and nanostructures are obtained by planarization of an evaporated titanium film. The dimensions of the structures are defined by the electron beam lithography resolution and the etching recipe. The third dimension is given by the titanium or any other metal thickness and can be controlled down to few nanometers thanks to the planarization step.

Generation of nanostructures on metals by laser ablation in liquids: new results

Surface nanostructuring of titanium, nickel, molybdenum, and tungsten by ablation with pico- and femtosecond laser pulses in liquids is studied experimentally for the first time. The morphology and properties of obtained nanostructures are investigated using a field emission scanning electron microscope and Raman spectroscopy. The size of nanostructures depends on the laser pulse duration and energy density and on the target material. As a rule, the size distribution of structures is bimodal. Potential applications of such nanostructured substrates are discussed.

Investigations of titanium nanostructures on Si(111) 7×7 by means of scanning tunnelling microscopy and spectroscopy

The aim of this paper were investigations of the growth of Ti nanostructures created by means of an electron gun on Si(111)-(7×7) with the coverage below 0.1 ML. Titanium was deposited on the Si substrate at 673 K. The Ti nanostructures after deposition and subsequent annealing processes were imaged in situ by means of UHV STM. The current imaging tunnelling spectroscopy (CITS) showed a contrast between the semiconducting substrate and Ti nanostructures. Some of the I V characteristics revealed the step-like character typical for the quantum size or Coulomb blockade effects. Annealing of the samples in the range of 673 K to 943 K led to appearing of the r19×r19 reconstruction. This reconstruction appeared at the cost of Ti nanostructures as a result of Ti atoms diffusion into Si sublayers.

Titanium nanostructures made by local oxidation with the atomic force microscope

Surfaces can be oxidized under ambient conditions with the tip of a scanning probe microscope when applying a voltage between surface and tip. The oxidation process is voltage- and humidity-dependent, and can be explained in terms of anodic oxidation. Sufficiently thin metal films (e.g., Ti or Al) can be completely oxidized down to the substrate, enabling the direct writing of nanostructures. We report on the fabrication and electrical measurements of Ti lines and Ti/TiO x /Ti junctions defined in titanium thin films having a thickness smaller than 10 nm.