Shuangbao Wang

Resistive switching behavior of photochemical activation solution-processed thin films at low temperatures for flexible memristor applications

This study explores deep ultraviolet photochemically activated solution-processed metal-oxide thin films at room temperature for fabrication of flexible memristor active resistive layers. An annealing treatment was not required during the process. Solution processed undoped and Mn-doped ZnO thin films served as active layers in the resistive random access memory structure, prepared at 145 °C. The carrier transports in high and low electrical fields were dominated by Frenkel–Poole emission and thermionic emission, respectively. The trap energy level, which originated primarily from Vo or the singly charged oxygen vacancy, was calculated at 0.49 eV. A flexible structure consisting of Ag/DUV-ZnO/indium tin oxide/polyethylene terephthalate was fabricated successfully and its mechanical performance was investigated.

Polymer nanopillar array with Au nanoparticle inlays as a flexible and transparent SERS substrate

We report a facile and efficient way to fabricate a highly flexible, transparent and efficient surface-enhanced Raman scattering (SERS) substrate, in which Au nanoparticles (NPs) were embedded into the polymeric nanopillars via a nanoimprint lithography (NIL) method and using an anodic aluminum oxide (AAO) template. The obtained substrate exhibits prominent reproducibility and high sensitivity to Rhodamine 6G (R6G). Moreover, it possesses excellent transparency and flexibility. The SERS intensity acquired from these substrates almost remains constant after 200 bending cycles. Compared with traditional SERS substrates, this substrate represents a novel format with unique advantages, such as being highly flexible, transparent, lightweight, portable and easy to handle. More importantly, it can be scaled up for high-throughput production with low cost.

Dynamical thermal metamaterial response at terahertz frequencies

ABSTRACT Utilizing terahertz time domain spectroscopy, we have characterized the electromagnetic response of a planar array of complementary square metal frames fabricated upon a high resistivity Si substrate, and between the two layers existed an important ferroelectric layer strontium titanate(STO). The resonance frequency dependent magnetic and electric resonances are in excellent agreement with theory. We demonstrate, it has two distinctive reflection dips through reconfigures the metamaterial by etched a rectangular stripe, and the former metamaterial has only one resonance frequency. Cooling the metamaterial from 400 K to 200 K causes excellent blue shift. The resonance shift is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. Because of the universality of metamaterial response over many decades of frequency, these results have implications for other regions of the electromagnetic spectrum.

Synthesis of barium strontium titanate quasi photonic crystals with nanopore arrays by sol–gel technique

ABSTRACT We report on the synthesis, characterization and optical properties of barium strontium titanate (BST) quasi photonic crystals (PCs) through a sol–gel technique with the porous alumina template (PAT). The structure, morphology and pore-size distribution of the samples were characterized by SEM, XRD and EDS, The Ba0.6Sr0.4TiO3 PCs of crystalline cubic phase with uniform pore size and ordered arrange were successfully synthesized. The obtained quasi BST PCs not only show that the nanostructure has spatially periodical orderly arrangement, but also exhibit good optical transmittance properties. The advantage of this sol–gel technique with PAT to fabricate ferroelectric (FE) nanopore arrays lies in its low cost and simplicity. This study opens a pathway for the effective fabrication and studies of FE nanopore arrays in uniquely large area.