While various crystalline carbon allotropes, including graphene, have been actively investigated, amorphous carbon (a-C) thin films have received relatively little attention. The a-C is a disordered form of carbon bonding with a broad range of the CC bond length and bond angle. Although accurate structural analysis and theoretical approaches are still insufficient, reproducible structure-property relationships have been accumulated. As the a-C thin film is now adapted as a hardmask in the semiconductor industry and new properties are reported continuously, expectations are growing that it can be practically used as active materials beyond as a simple sacrificial layer. In this perspective review article, after a brief introduction to the synthesis and properties of the a-C thin films, their potential practical applications are proposed, including hardmasks, extreme ultraviolet (EUV) pellicles, diffusion barriers, deformable electrodes and interconnects, sensors, active layers, electrodes for energy, micro-supercapacitors, batteries, nanogenerators, electromagnetic interference (EMI) shielding, and nanomembranes. The article ends with a discussion on the technological challenges in a-C thin films. 

Amorphous Carbon Films for Electronic Applications

Influence of aminated graphene nanosheets on electro–optical performance and nonlinear optical properties of nematic liquid crystal

The electron field emission (EFE) properties of nitrogenated carbon nanotips (NCNTPs) were studied under high-vacuum conditions. The NCNTPs were prepared in a plasma-assisted hot filament chemical vapor deposition system using CH4 and N2 as the carbon and nitrogen sources, respectively. The work functions of NCNTPs were measured using x-ray photoelectron spectroscopy. The morphological and structural properties of NCNTPs were studied by field emission scanning electron microscopy, micro-Raman spectroscopy, and x-ray photoelectron spectroscopy. The field enhancement factors of NCNTPs were calculated using relevant EFE models based on the Fowler-Nordheim approximation. Analytical characterization and modeling results were used to establish the relations between the EFE properties of NCNTPs and their morphology, structure, and composition. It is shown that the EFE properties of NCNTPs can be enhanced by the reduction of oxygen termination on the surface as well as by increasing the ratio of the NCNTP height to the radius of curvature at its top. These results also suggest that a significant amount of electrons is emitted from other surface areas besides the NCNTP tops, contrary to the common belief. The outcomes of this study advance our knowledge on the electron emission properties of carbonnanomaterials and contribute to the development of the next-generation of advanced applications in the fields of micro- and opto-electronics.

Structure- and composition-dependent electron field emission from nitrogenated carbon nanotips

Comparison study of the structure, dielectric function, and two-photon absorption cross-section of BiOI and Ag/BiOI nanomaterials

Investigation of linear and nonlinear optical properties of amorphous carbon nanofilms prepared by electron beam evaporation

In this research, we investigated the linear and nonlinear optical properties of Al alloyed Ni nanofilms prepared by e-beam evaporation on glass substrates. Thin layers of Ni and Al were deposited sequentially at room temperature on glass substrates. The intermixed layers revealed different structures of Ni and Al formations due to a spontaneous intermixing process with controlled stoichiometric ratios. The Maxwell–Garnett theory for the composite matrix formed by the Ni–Al​ inclusions and alloys was used to predict the complex dielectric functions of the fabricated films. Since Al is a trivalent element, the electron population density was enhanced near the Ni–Al atomic sites with an increase in the Al content. This enhancement boosted the nonlinear absorption in the alloyed films. The composite model was used to interpret this enhancement of the nonlinear optical behavior over pure Ni films. The results are discussed in relation to future applications. 

Kawther M. Al-Adamat

Papers

Investigation of linear and nonlinear optical properties of amorphous carbon nanofilms prepared by electron beam evaporation

Investigating the linear and nonlinear optical properties of Al alloyed Ni nanofilms in the cw regime