Embedded copper mesh coatings with low sheet resistance and high transparency were formed using a low-cost Cu seed mesh obtained with a magnetron sputtering on a cracked template, and subsequent operations electroplating and embedding in a photocurable resin layer. The influence of the mesh size on the optoelectric characteristics and the electromagnetic shielding efficiency in a wide frequency range is considered. In optimizing the coating properties, a shielding efficiency of 49.38 dB at a frequency of 1 GHz, with integral optical transparency in the visible range of 84.3%, was obtained. Embedded Cu meshes have been shown to be highly bending stable and have excellent adhesion strength. The combination of properties and economic costs for the formation of coatings indicates their high prospects for practical use in shielding transparent objects, such as windows and computer monitors.
1 June 2014 in Semiconductor Science and Technology
We have prepared thin indium oxide films by the autowave oxidation reaction. Measurements of temperature dependence of resistivity, Hall carrier concentration and Hall mobility have been conducted in the temperature range 5?272 K. Before ultraviolet (UV) irradiation, the indium oxide film had a semiconductor-like temperature dependence of resistivity ? and the ratio of ?(5 K)/?(272 K) was very limited (?1.2). It was found that after UV irradiation of the In2O3 film, the metal?semiconductor transition (MST) was observed at ?100 K. To show that this MST is reversible and repeatable, two full cycles of ?absence of MST?presence of MST? have been done using UV irradiation (photoreduction) as the induced mechanism and exposure to an oxygen environment as the reversible mechanism, respectively. MST in transparent conducting oxide (TCO) is possibly associated with the undoped structure of metal oxide, which has some disorder of oxygen vacancies. It was suggested that reversible UV induced metal?semiconductor transition would occur in other TCOs.
Aluminum-doped zinc oxide thin films have been grown by atomic layer deposition at a temperature of 200°C. Using X-ray diffraction, it has been established that the ZnO:Al thin films exhibits...
Thin films have been produced via a spray method from commercially available single-walled carbon nanotubes (SWCNTs). A SWCNT film thickness has ranged from ~10 to ~80 nm. The SWCNT diameter...
The single-walled carbon nanotube-based thin films with a thickness from 11 ± 3 to 157 ± 18 nm have been formed using vacuum filtration. The thermal conductivity of the thin films as a function of thickness and temperature up to 450 K has been studied by the 3ω technique. It has been found that, in the region of 49 nm, the supplied heat from a gold strip started propagating with the high efficiency to the thin film plane. The thermal conductivity of the thin films with a thickness of 49 ± 8 nm was measured using the 3ω technique for bulk samples. It has been found that the thermal conductivity of the single-walled carbon nanotube-based thin films strongly depends on their thickness and temperature. The thermal conductivity sharply (by a factor of ~60) increases with an increase in thickness from 11 ± 3 to 65 ± 4 nm. In addition, it has been observed that the thermal conductivity of the thin film with a thickness of 157 ± 18 nm rapidly decreases from 211 ± 11 to 27.5 ± 1.4 W m–1 K–1 at 300 and 450 K, respectively.
Highly efficient shielding materials, transparent in the visible and IR ranges are becoming important in practice. This stimulates the development of cheap methods for creating transparent conductors with low sheet resistance and high optical transparency. This work presents a complex approach based on preliminary modeling of the shielding characteristics of two-layer sandwich structures based on irregular aluminum mesh (IAM) formed by the cracked template method. Experimentally measured spectral dependences of the transmission coefficient of single-layer IAM are used as a reference point for modeling. According to the simulation results, two types of sandwich structures were designed using IAM, with varying filling factors and a fixed PMMA layer thickness of 4 mm. The experimentally measured shielding characteristics of the sandwich structures in the range of 0.01–7 GHz are in good agreement with the calculated data. The obtained structures demonstrate a shielding efficiency of 55.96 dB and 65.55 dB at a frequency of 3.5 GHz (the average range of 5G communications). At the same time, their optical transparency at a wavelength of 550 nm are 84.07% and 75.78%, respectively. Our sandwich structures show electromagnetic shielding performance and uniform diffraction pattern. It gives them an advantage over structures based on regular meshes. The obtained results highlight the prospect of the proposed comprehensive approach for obtaining highly efficient, low-cost optically transparent shielding structures. Such materials are needed for modern wireless communication systems and metrology applications.