Yuanjiang Lv

Bio: Yuanjiang Lv is an academic researcher from Henan University of Science and Technology. The author has contributed to research in topics: Materials science & Nanoparticle. The author has an hindex of 2, co-authored 6 publications receiving 15 citations.

Effects of Ag contents on the microstructure and SERS performance of self-grown Ag nanoparticles/Mo–Ag alloy films

Abstract: Abstract Ag nanoparticles/Mo–Ag alloy films with different Ag contents were prepared on polyimide by magnetron sputtering. The effects of Ag contents on the microstructure of self-grown Ag nanoparticles/Mo–Ag alloy films were investigated using XRD, FESEM, EDS and TEM. The Ag content plays an important role in the size and number of uniformly distributed Ag nanoparticles spontaneously formed on the Mo–Ag alloy film surface, and the morphology of the self-grown Ag nanoparticles has changed significantly. Additionally, it is worth noting that the Ag nanoparticles/Mo–Ag alloy films covered by a thin Ag film exhibits highly sensitive surface-enhanced Raman scattering (SERS) performance. The electric field distributions were calculated using finite-difference time-domain analysis to further prove that the SERS enhancement of the films is mainly determined by “hot spots” in the interparticle gap between Ag nanoparticles. The detection limit of the Ag film/Ag nanoparticles/Mo–Ag alloy film for Rhodamine 6G probe molecules was 5 × 10−14 mol/L. Therefore, the novel type of the Ag film/Ag nanoparticles/Mo–Ag alloy film can be used as an ideal SERS-active substrate for low-cost and large-scale production.

Effect of Annealing on the Microstructure and SERS Performance of Mo-48.2% Ag Films

Abstract: Mo-48.2% Ag films were fabricated by direct current (DC) magnetron sputtering and annealed in an argon atmosphere. The effects of annealing on the surface morphology, resistivity and surface-enhanced Raman scattering (SERS) performance of Mo-48.2% Ag films were investigated. Results show a mass of polyhedral Ag particles grown on the annealed Mo-48.2% Ag films’ surface, which are different from that of as-deposited Mo-Ag film. Moreover, the thickness and the resistivity of Mo-48.2% Ag films gradually decrease as the annealing temperature increases. Furthermore, finite-difference time-domain (FDTD) simulations proved that the re-deposition Ag layer increases the “hot spots” between adjacent Ag nanoparticles, thereby greatly enhancing the local electromagnetic (EM) field. The Ag layer/annealed Mo-48.2% Ag films can identify crystal violet (CV) with concentration lower than 5 × 10−10 M (1 mol/L = 1 M), which indicated that this novel type of particles/films can be applied as ultrasensitive SERS substrates.

Platinum Hillocks in Pt/Ti Film Stacks Deposited on Thermally Oxidized Si Substrate : Semiconductors

Abstract: The stress dependence of platinum hillock formation during post thermal cycling was investigated in Pt/Ti electrode stacks. Annealing temperatures were varied from room temperature (RT) to 650°C. High compressive stress was generated during electrode annealing by the Ti diffusion into the platinum layer followed by oxidation in the platinum grain boundaries. The compressive stress was the major driving force for the hillock formation on the platinum surface. Thus, the Ti glue layer was oxidized before platinum deposition to reduce the Ti diffusion. The Pt/TiOx electrode stack retained its smooth platinum surface after the electrode annealing of 650°C for 30 min in O2. The Pt/TiOx interface remained flat even after the ferroelectric annealing at 800°C, which was performed after SrBi2Ta2O9 (SBT) deposition. Moreover, the remanent polarization (2Pr) of the SBT capacitor was increased to 17 µC/cm2 on the Pt/TiOx electrode stack, up from 13 µC/cm2, which was the value on the Pt/Ti electrode stack.

Effects of Ag contents on the microstructure and SERS performance of self-grown Ag nanoparticles/Mo–Ag alloy films

Abstract: Abstract Ag nanoparticles/Mo–Ag alloy films with different Ag contents were prepared on polyimide by magnetron sputtering. The effects of Ag contents on the microstructure of self-grown Ag nanoparticles/Mo–Ag alloy films were investigated using XRD, FESEM, EDS and TEM. The Ag content plays an important role in the size and number of uniformly distributed Ag nanoparticles spontaneously formed on the Mo–Ag alloy film surface, and the morphology of the self-grown Ag nanoparticles has changed significantly. Additionally, it is worth noting that the Ag nanoparticles/Mo–Ag alloy films covered by a thin Ag film exhibits highly sensitive surface-enhanced Raman scattering (SERS) performance. The electric field distributions were calculated using finite-difference time-domain analysis to further prove that the SERS enhancement of the films is mainly determined by “hot spots” in the interparticle gap between Ag nanoparticles. The detection limit of the Ag film/Ag nanoparticles/Mo–Ag alloy film for Rhodamine 6G probe molecules was 5 × 10−14 mol/L. Therefore, the novel type of the Ag film/Ag nanoparticles/Mo–Ag alloy film can be used as an ideal SERS-active substrate for low-cost and large-scale production.