Effect of radical on defect and molecular structure of monolayer MoS2 by low temperature plasma treatment

The aim of this study is to form the sulfur defects on monolayer molybdenum disulfide (MoS2) by low temperature microwave plasma treatment suppressing disturbance of molecular structure. CVD-grown and plasma treated multilayer MoS2 surface were analyzed to investigate the effects of H2 and Ar plasma treatment on sulfur defects and molecular structure. It was found that the disturbance of molecular structure was suppressed in the H2 plasma treatment compared to the Ar plasma treatment. Varying the incident ratio of hydrogen ions H+ and radicals H*, the influences of H2 plasma treatment with high and low H*/H+ ratio on monolayer MoS2 structure were discussed. As a result of X-ray photoelectron spectroscopy, Raman spectroscopy and photoluminescence analysis, sulfur defects increased with the increase in total amount of radical incident on MoS2. In addition, it is speculated that the etching with radical contributed to form sulfur defects suppressing the disturbance of molecular structure.

Tunable physical properties of Al-doped ZnO thin films by O2 and Ar plasma treatments

Al-doped ZnO (AZO) is a promising transparent conducting oxide that can replace indium tin oxide (ITO) owing to its excellent flexibility and eco-friendly characteristics. However, it is difficult to immediately replace ITO with AZO because of the difference in their physical properties. Here, we study the changes in the physical properties of AZO thin films using Ar and O2 plasma treatments. Ar plasma treatment causes the changes in the surface and physical properties of the AZO thin film. The surface roughness of the AZO thin film decreases, the work function and bandgap slightly increase, and the sheet resistance significantly decreases. In contrast, a large work function change is observed in the AZO thin film treated with O2 plasma; however, the change in other characteristics is not significant. Therefore, the results indicate that post-treatment using plasma can accelerate the development of high-performance transparent devices.

Hibiscus sabdariffa L. calyces’ and argon DBD plasma: potential eco-friendly cleaners for fire-damaged silver gelatin prints

Purpose This paper aims at examining the potentiality of using Hibiscus sabdariffa L. calyces’ (Hs) aqueous extract to remove soot stains from the surface of fire-damaged silver gelatin prints. It further studies the cleaning efficiency and impact of both a contact method and a noncontact method with argon dielectric barrier discharge plasma (DBD Ar. plasma) on the different properties of silver gelatin prints. Accordingly, it prompts using economic, eco-friendly materials and methods in the photograph conservation field. Design/methodology/approach To achieve the aims of this paper, four silver gelatin prints were stained with soot and treated with the (Hs) aqueous extract as a contact method and DBD Ar. plasma combined with the aqueous extract as a noncontact method. The assessment was carried out using digital microscopy, atomic force microscopy and spectrophotometer to study the efficiency of the tested treatments and their impact on the surface of the photographs. FTIR was used to monitor the state of the binder after cleaning. Furthermore, the pH and the mechanical properties were measured. Findings The contact method resulted in lower concentrations of (Hs) extract that efficiently cleaned the surface without causing any stains or damage to the treated photographs. The noncontact method (plasma with an aqueous extract) proved to be less effective in cleaning and made the binder more susceptible to deterioration. Originality/value This paper reveals the success of (Hs) aqueous extract in cleaning soot on vulnerable photographs’ surfaces.

Enhancement of Electrical Properties of Sol–Gel Indium–Tin–Oxide Films by Microwave Irradiation and Plasma Treatment

We proposed the enhancement of the electrical properties of solution-processed indium–tin–oxide (ITO) thin films through microwave irradiation (MWI) and argon (Ar) gas plasma treatment. A cost- and time-effective heat treatment through MWI was applied as a post-deposition annealing (PDA) process to spin-coated ITO thin films. Subsequently, the sheet resistance of MWI ITO thin films was evaluated before and after plasma treatment. The change in the sheet resistance demonstrated that MWI PDA and Ar plasma treatment significantly improved the electrical properties of the ITO thin films. Furthermore, X-ray photoelectron spectroscopy and X-ray diffraction analyses showed that the electrical properties of the ITO thin films were enhanced by the increase in oxygen vacancies due to the ion bombardment effect of high-energy plasma ions during Ar plasma treatment. Changes in the band gap structure of the ITO thin film due to the ion bombardment effect were also analyzed. The combination of MWI PDA and Ar plasma treatment presents new possibilities for improving the high-conductivity sol–gel ITO electrode.