As the scaling technology in the silicon-based semiconductor industry is approaching physical limits, it is necessary to search for proper materials to be utilized as alternatives for nanoscale devices and technologies. On the other hand, carbon-related nanomaterials have attracted so much attention from a vast variety of research and industry groups due to the outstanding electrical, optical, mechanical and thermal characteristics. Such materials have been used in a variety of devices in microelectronics. In particular, graphene and carbon nanotubes are extraordinarily favorable substances in the literature. Hence, investigation of carbon-related nanomaterials and nanostructures in different ranges of applications in science, technology and engineering is mandatory. This paper reviews the basics, advantages, drawbacks and investigates the recent progress and advances of such materials in micro and nanoelectronics, optoelectronics and biotechnology.

Traditional methods for detection of lead ions in water samples are costly and time-consuming. In this work, an accurate smartphone-based colorimetric sensor was developed utilizing a novel machine learning algorithm. In the presence of Pb²⁺ ions in the solution of specifically functionalized gold nanoparticles, the color of solution turns from red to purple. Indeed, the color variation of the solution is proportional to Pb²⁺ concentration. The smartphone camera captures the corresponding color change, and the image is processed by an efficient artificial intelligence protocol. The nonlinear regression approach was used for concentration estimation, in which the parameters of the proposed model are obtained using a new feature extraction algorithm. In prediction of Pb²⁺ concentration, the average absolute error and root-mean-square error were 0.094 and 0.124, respectively. The influence of pH of the medium, temperature, oligonucleotide concentration, and reaction time on the performance of the proposed sensor was carefully investigated and understood to achieve the best sensor response. This novel sensor exhibited good linearity for the detection of Pb²⁺ in the concentration range of 0.5–2000 ppb with a detection limit of 0.5 ppb.

Perovskite solar cells (PSCs) have been able to raise new hopes for a revolution in solar cell technology. However, there are many challenges which need to be resolved in order to reveal the true potential of this technology. An issue which should be addressed in designing PSCs is the metal-hole transporting material (HTM) contact’s property. One of the most promising inorganic HTMs for PSCs is Nickel oxide. Although NiO has been extensively studied in the literature, to the best of our knowledge metal-NiO junctions have never been studied experimentally. In this work, metal-NiO contacts have been investigated to indicate a novel route to choose proper metals in designing PSCs based on NiO as the HTM. Thus, NiO layers with four various metals have been fabricated and comprehensively explored. The contacts have been characterized using the transmission line method (TLM), and a contact resistivity ranging from about 2052 to 34 mΩ⋅cm² was observed. I-V characteristics showed ohmic behavior in all metal-NiO cases. These results indicate that Fermi level pinning occurs at the valence band edge of the NiO. Further discussions resulted in suggesting Nickel as the most applicable candidate on NiO have been also included.

An efficient terahertz (THz) photoconductive antenna (PCA), as a major constituent for the generation or detection of THz waves, plays an essential role in bridging microwave-to-photonic gaps. Here, we propose an impressive approach comprising the use of arrayed zinc oxide nanorods (ZnO NRs) as an optical nanoantenna over an anti-reflective layer (silicon nitride) in the antenna gap to boost the photocurrent and consequently the THz signal. The numerical approach applied in investigating the optical behavior of the structure, demonstrates a significant field enhancement within the LT-GaAs layer due to the optical antenna performing simultaneously as a concentrator and an antireflector which behaves as a graded-refractive index layer. ZnO NRs have been fabricated on the PCA gap using the hydrothermal method as a simple, low cost and production compatible fabrication method compared to other complex methods used for the optical nanoantennas. Compared to the conventional PCA with a traditional antireflection coating, the measured THz power by time domain spectroscopy (TDS) is increased more than 4 times on average over the 0.1–1.2 THz range.