• M K JAYARAJ

Articles written in Bulletin of Materials Science

• Effects of insulating layer on the performance of thin film electroluminescent devices

Thin film electroluminescent devices were fabricated with active layer of ZnS:Mn and different insulators viz Sm2O3, Eu2O3, Na3A1F6, MgF2, CeO2 and SiO in MIS and MISIM structure. The threshold voltage for light emission in AC thin film electroluminescent devices of MIS and MISIM structures is found to depend on the dielectric properties of insulating materials. The observed threshold voltage for these devices and its variations for devices with different insulators are explained using the equivalent circuit for the device and the dielectric properties of the insulting material used for the preparation of device. Variation of threshold voltage with operating time is also studied for some of the devices.

• Chemical vapour deposited graphene: substrate pre-treatment, growth and demonstration as a simple graphene-based SERS substrate

In chemical vapour deposition (CVD) of graphene, surface roughness and purity of the copper substrate are very crucial for obtaining uniform films. Even though electrochemical polishing is an effective technique for obtaininghomogeneous graphene films, most of the experiments adopt complex experimental parameters like electrolyte heating, stirring and use of additives for better results. These are not applicable to thin copper foils used in CVD of graphene. In the present study, a simple electrochemical procedure is developed for deposition of high-quality graphene films with good coverage. The depositions of graphene films on bare and polished copper foils for the same growth conditions are analysed using various microscopic techniques. The uniformly grown graphene on copper is then directly employed as a surface-enhanced Raman scattering (SERS) substrate along with plasmonic silver nanoparticles. A simple SERS substrate having a reasonable detection limit of 10$^{−10}$ M for R6G is achieved with uniform SERS signals over a large area. Thehomogeneity of SERS substrate can be attributed to the uniformity of the deposited graphene film. A simple and efficient SERS substrate using conventional methods is achieved through the incorporation of chemical vapour deposited graphene. The study covers the growth of CVD graphene film starting from substrate pre-treatment, various analyses of the film andfinally the application in SERS.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020