We investigate the operation of multitip silicon field emitters with new-type bilayer metal—fullerene protective coatings in technical vacuum. The experiments indicate that such cathodes ensures emission current densities averaged over the cathode surface of about 0.5 A/cm² and can be used in high-voltage devices including microwave electronic instruments as well as portable X-ray sources.

Graphene derivatization to either engineer its physical and chemical properties or overcome the problem of the facile synthesis of nanographenes is a subject of significant attention in the nanomaterials research community. In this paper, we propose a facile and scalable method for the synthesis of thiolated graphene via a two-step liquid-phase treatment of graphene oxide (GO). Employing the core-level methods, the introduction of up to 5.1 at.% of thiols is indicated with the simultaneous rise of the C/O ratio to 16.8. The crumpling of the graphene layer upon thiolation without its perforation is pointed out by microscopic and Raman studies. The conductance of thiolated graphene is revealed to be driven by the Mott hopping mechanism with the sheet resistance values of 2.15 kΩ/sq and dependable on the environment. The preliminary results on the chemiresistive effect of these films upon exposure to ethanol vapors in the mix with dry and humid air are shown. Finally, the work function value and valence band structure of thiolated graphene are analyzed. Taken together, the developed method and findings of the morphology and physics of the thiolated graphene guide the further application of this derivative in energy storage, sensing devices, and smart materials.

The dynamic characteristics of field emission from nanocarbon films subjected to microsecond electric field pulses are studied. The emission curves exhibit hysteresis the parameters of which are...

Numerous carbonic nano-structured materials were reported to demonstrate electron emission in moderate electric field (1 kV/mm or less), even if their surface morphology shows no edges or tips capable of strong local field enhancement. In many such cases, the actual mechanism of emission facilitation remains unclear, partially due to the complex structure of the investigated materials usually representing a three-dimensional system of domains with different properties. In the presented work, we investigated a simpler, quasi-2d system, presumably providing better possibilities for unambiguous description of the emission mechanism. Emitters were produced by chemical deposition of small amounts of graphitic carbon at silicon substrates. The films had nano-island structure and demonstrated good emission properties with threshold electric field as low as 550 V/mm.

Photo-induced current through nanocomposite heterojunction structures consisting of a TiO ₂ coating activated with embedded gold nanoparticles on top of Si, SiO ₂ , and columnar structured SiO ₂ is studied. The highest photo-activity in the visible part of the spectrum is found in the composite containing pillar-like silicon dioxide nanostructures. Experimental results were qualitatively explained on the basis of Franz-Keldysh effect taking into account the effects of electrical inhomogeneities appearing at charged nanoparticles. It is established that processes at the interface between silicon and noble metal nanoparticles play an important role in charge carrier photo-generation which opens a new opportunity to tune the photo-response of a nanocomposite via changing heterostructure topology.